Photocatalytic Degradation of Salicylic Acid and ...

Int’l Conference of 5th International Conference on Advances in Engineering and Technology (ICAET'2016)

June 8-9, 2016 New Jersey, USA

Editors: Prof. Kazuaki Maeda Prof. Dr. Alina BUTU ISBN 978-93-84422-69-1

Organized By:

International Institute of Engineers http://iieng.org/

Program Committee (ICAET’2016) Conference Chair Prof. Dr. Thaweesak Yingthawornsuk, King Mongkut’s University of Technology Thonburi, Thailand Prof. Dr. Kazuaki Maeda, Chubu University, Matsumoto, Kasugai, Aichi, Japan Prof. Hirotaka Sato, Nanyang Technological University (NTU), Singapore

Co-Chair Associate Prof. Dr. Kirk Scott, University of Alaska Anchorage, Alaska, USA Dr. Michel PLAISENT, University of Quebec in Montreal, Canada Prof. Dr. Parvinder S. Sandhu, Rayat-Bahra University, India Dr. Md. Aminur Rahman, Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia (UPM), Malaysia IEEE Fellow Prof. Dr. Alan Chin-Chen Chang, Feng Chia University, Taiwan

Technical Committee Associate Prof. Dr. Bekim Fetaji, South East European University, Faculty of Contemporary Sciences and Technologies, Ilindenska bb, 1200 Tetovo, Republic of Macedonia Haruhiro Fujita, Department of Information Systems, Niigata University for International and Information Studies, Japan Prof. Kei Eguchi, Professor, Department of Information Electronics, Fukuoka Institute of Technology, Fukuoka, Japan Dr. Ahmed ARARA, University of Tripoli, Computer Engineering department, Libya Prof. Dr.V.R.Sanal Kumar, Professor and Aerospace Scientist, Department of Aeronautical Engineering, Kumaraguru College of Technology, Coimbatore, Tamil Nadu, India Prof. Wei-Hua He, Associate Prof., Soochow University, Taipei, Taiwan Prof. Dr. Bekir Karlık, Department of Computer Eng., Selçuk University, Konya, Turkey Alireza Nazem, PhDc, Underwater Robotics Research Group (URRG), Universiti Sains Malaysia, Malaysia Asst. Prof. Dr. Chaiyapon Thongchaisuratkrul, Mahidol University, Thailand Prof. Felix T.S. Chan, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, HK Prof. Dr. Abu Talib Othman, Malaysian Institute of Information Technology, Universiti Kuala Lumpur, Malaysia Prof. Dr. Mohamed Othman, Dept of Comm Tech and Network, Universiti Putra Malaysia, Malaysia Assoc. Prof. Dr. Mohammad Laghari, Department of Electrical Engineering, UAE University, United Arab Emirates Dr. Clement Temaneh Nyah, Electronics and Computer Engineering Dept., University of Namibia, Namibia Dr. Hsiao-Wei Hu, Information Management, Fu Jen Catholic University, Taiwan Prof. Dr. Rosalina Abdul Salam, Faculty of Science & Technology, Universiti Sains Islam Malaysia Prof. Dr. Muhibul Haque Bhuyan Muhibul, Department: Electrical and Electronic Engineering, Green University of Bangladesh, Bangladesh Prof. Dr. VINAYADATT KOHIR, Department of E & CE, P.D.A. College of Engineering, Iceland Prof. Tae-Won Park, Professor, Ajou University, Suwon, Korea Prof. R.G. Chouksey, Head, Department of Vocational Education and Entrepreneurship Development, National Institute of Technical Teachers' Training & Research, Bhopal, India Prof. Ali. Azadeh, Professor, Department of Industrial Engineering and Center of Excellence for Intelligent-Based Mechanics, University College of Engineering, University of Tehran, Iran Prof. Sungwook Park, Hanyang University, Seoul, Korea

Program Committee (ICAET’2016) Contd. Prof. Nishith Dubey, National Institute of Technical Teachers' Training & Research, Bhopal, India Prof. Hyungu Roh, Induk University, Seoul, Korea, Dr. J. L. Bhagoria, Professor, Department Of Mechanical Engineering, Maulana Azad National Institute Of Technology, BHOPAL, India Prof. Dr. Mohamed BOUAFIA, Institut of optics and precision mechanics, applied optics laboratory, University of Setif, Algeria Dr. Jagannath. Korody , Professor, Manipal Institute of Technology, India Prof. Dr. Omar Badran, Department of Mechanical Engineering, Al-Balqa` Applied University/Faculty of Engineering Technology, Jordan Prof. Sarabjit Singh, Head & Associate Professor, Department of Industrial & Production Engineering, National Institute of Technology, Jalandhar, India Prof. Dr. Yi-Xian Qin, Department of Biomedical Engineering, Stony Brook University, New York

PREFACE Dear Distinguished Delegates, Colleagues and Guests, The IIE Organizing Committee warmly welcomes our distinguished delegates and guests at International Institute of Engineers’ ICAET’2016 Int’l Conference scheduled on June 8-9, 2016 New Jersey, USA. The main themes and tracks are Advances in Engineering and Technology. This conference is managed and sponsored by International Institute of Engineers and assisted by University of Johannesburg and University of Quebec. IIE is striving hard to compile the research efforts of scientists, researchers and academicians across the broad spectrum of Science, Engineering and Technology. These conferences are aimed at discussing the wide range of problems encountered in present and future high technologies among the research fraternity. The conferences are organized to bring together the members of our international community at a common platform, so that, the researchers from around the world can present their leading-edge work. This will help in expansion of our community’s knowledge and provide an insight into the significant challenges currently being addressed in that research. The conference Program Committee is itself quite diverse and truly international, with membership from the America, Australia, Europe, Asia and Africa. The conferences has solicited and gathered technical research submissions related to all aspects of major conference themes and tracks. This proceeding records the fully refereed papers presented at the conference. All the submitted papers in the proceeding have been peer reviewed by the reviewers drawn from the scientific committee, external reviewers and editorial board depending on the subject matter of the paper. Reviewing and initial selection were undertaken electronically. After the rigorous peer-review process, the submitted papers were selected on the basis of originality, significance, and clarity for the purpose of the conference. The main goal of these events is to provide international scientific forums for exchange of new ideas in a number of fields that interact indepth through discussions with their peers from around the world. The program has been structured to favor interactions among attendees coming from many diverse horizons, scientifically, geographically, from academia and from industry. We would like to thank the program chairs, organization staff, and the members of the program committee for their work. We like to thank and show gratitude to Editors from IIE. We are grateful to all those who have contributed to the success of IIE June. 8-9, 2016 New Jersey, USA Conference. We hope that all participants and other interested readers benefit scientifically from the proceedings and also find it stimulating in the Process in their quest of achieving greater heights. Finally, we would like to wish you success in your technical presentations and social networking.

We hope you have a unique, rewarding and enjoyable week at IIE Conference at vibrant New Jersey, USA. With our warmest regards,

Organizing Committee June 8-9, 2016 New Jersey, USA

INDEX 5th International Conference on Advances in Engineering and Technology (ICAET'2016) June 8-9, 2016 New Jersey, USA Paper ID

Title of the Paper and Authors

Page No.

E0616008

Large Scale Data Sets Clustering Umesh Kumar, and Ashish Mishra

1

E0616010

Comparison of Four Different Methods of the Ant Colony Optimization Algorithm Applied to Crew Dispatch for Network Service in an Electricity Utility Tiago Milagres Miranda, Paulo Henrique Baumann, Fabio Romero, João Castilho Neto, Alden Uehara Antunes, Dário Takahata, Leonardo H. T. Ferreira Neto, Luisa Morais Azevedo, Ângelo César Lorenzo Alves, and Sérgio L. P. de Castro Valinho

6

E0616011

Crew Dispatch for Network Services in an Electricity Utility Using Ant Colony Optimization Methodology Paulo H. Baumann, Tiago M. Miranda, Fabio Romero, João Castilho Neto, Alden U. Antunes, Dário Takahata, Leonardo H. T. Ferreira Neto, Ângelo C. L. Alves, Luisa M. Azevedo, and Sérgio L. P. C. Valinho

14

E0616027

Hydrodynamic Conditions and Photodegradation of Methyl Orange in a Fluidized Bed Photoreactor Reliance J. Mhlanga, Nhlanhla Nyembe, Haleden Chiririwa, and Aoyi Ochieng

23

E0616028

Photocatalytic Degradation of Salicylic Acid and Reduction of Cr(VI) using TiO2 Ramataobane K. Mphela, William Msimanga, Kwena Y. Pete, Haleden Chiririwa and Aoyi Ochieng

30

E0616034

Seamless Channel Spacing in Multiple Wavelength Fiber based Lasers M. Ajiya, J. A. Oladapo, U. G. Danbatta, and N. A. M. Ahmad Hambali

37

E0616036

Planning Public Spaces through Urban Lighting Roghiyeh Samani Parsa

42

E0616040

Simulation of Seismic Performance of Reinforced Concrete Verified with Experiment Melaku Sisay Abebe, and Hong sheng Qiu

45

E0616041

3D Model Identification using Histogram Normalization with Conformal factor Ruichen Jin, and Jongweon Kim

51

E0616042

Towards Environmental Sustainable Neighborhoods in Riyadh City Akram.R.Ahmed, and Khaled Abdullah Al-saud

56

E0616029

Software Configuration Management using the Dependency Information Junku Lee, Dongyeon Kim, and Sangjun Lee

68

ISBN 978-93-84422-69-1 Proceedings of 2016 5th International Conference on Advances in Engineering and Technology (ICAET'2016) New Jersey (Near NEW YORK), USA June 8-9, 2016

Large Scale Data Sets Clustering Umesh Kumar1, and Ashish Mishra2 1

Department of Electrical Engineering, Indian Institute of Technology Delhi, New Delhi-110016, India Email: [email protected] 2 Department of Electronics and Communication Engineering, IEC College of Engineering and Technology, Greater Noida UP- 201310, India. Email : [email protected]

Abstract: The real-world big data can be clustered along desired dimensions but it is limited in its applicability

to large-scale problems due to its high computational complexity, user’s desire, number of dimensions etc. Recently, many approaches have been proposed to accelerate the large scale data clustering. Unfortunately, these methods usually sacrifice quite a lot of information of the original data; incompetent to produce multiple clustering etc and don’t consider the geometrical, psychological and physiological interpretation of naturally occurring data whose representation may be parts-based in human brain. In this paper eight clustering algorithms are analyzed which is based on large scale data of eight different environment and dimensions to find out a universal framework for the representation and processing of knowledge. Our empirical study shows the encouraging results of the LSC-K algorithm in comparisons to state-of-the –art algorithms.

Keywords: Clustering, big data and analytics

1. Introduction Big data-the large volumes of data that are now produced in many fields-can present problems in storage, transmission, and processing, but their analysis may yield useful information and that information may be helpful for revenue i.e. products marketing, sells etc. extraction of useful information from a bulk data is a very challenging problem. In real word environment large scale data is available in text, images, audio, and video files etc with multiple dimensions. Now it is a challenge to cluster these data into user’s desire by using mathematical equations. With the aim of large scale data clustering, many methods have been proposed over the past decades [1]. Most of these algorithms are based on eigen-decomposition of matrices [2] and Euclidean geometry which have limitations on the shape of the clusters. To overcome this limitation of geometry, spectral clustering is proposed which adapt to a wider range of geometries and detect non-convex patterns and linearly non-separable clusters [3-4]. Spectral clustering has high computational complexity which is an unbearable burden for real-world big data applications [5]. In recent years, much effort has been given to design the algorithms to reduce the computational cost of the eigen-decomposition [6]. Another direction is to perform a reduction in the actual data size in order to reduce the computational cost [7-11]. These methods usually sacrifice quite a lot of information of the original data which may be useful for extracting or clustering information as per user’s desire. The question, then, is: can a clustering method give a clustering along the user-specified dimensions in realworld large data sets? The other question as: is it possible for a clustering algorithm to produce best performance

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for all type of real-world data sets and incorporate human perceptual aspects in processing. To find out the solution regarding these questions, an experimental study is carried out in this paper. The rest of the paper is organized as follows: in Section 2 provide a brief review of seven popular methods for clustering. Experimental evaluation is given in Section 3. Finally, concluding remarks are given in Section 4.

2. Clustering Methods To find the effectiveness clustering method among seven methods based common approaches. Total seven methods are compared to each other in terms of accuracy, mutual information and estimated time. Following, information of the methods are given as: LSC-R it is landmark-based spectral clustering using random sampling to select landmarks [13]. LSC-K It is landmark-based spectral clustering using k-means for selection of landmarks. These two LSC based methods depends on two parameters number of landmarks and nearest landmarks which are set to 500 and 6, respectively [13]. For the same number of landmarks are used for other methods also. NMF-subspace NMF is a matrix factorization algorithm that approximates a data matrix with two nonnegative matrices and the graph regularized NMF (GNMF) to incorporate the geometrical properties [14]. The signal subspace method and original k-means is also taken for analysis.

3. Experimental Evaluation In this section, several experiments are conducted to demonstrate the effectiveness of the given algorithms and various real world multidimensionality dataset.

3.1.

Data Sets

Experimental study carried out on seven real-world large scale data sets taken from UCI machine learning repository and personal homepage of Dr. Deng Cai. A brief description of the data sets is listed below: MNIST: A data set of handwritten digits from Yann LeCun’s page [12]. Each image is represented as a 784 dimensional vector. COIL20: It contains 20 categories. The images of each category were taken 5 degrees apart as the category is rotated on a turntable and each category has 72 images. The size of each image is 32X32 pixels, with 256 grey levels per pixel. Thus, each image is represented by a 1024-dimensional vector [12]. Isolet spoken letter recognition database: It contains 150 speakers who spoke the name of each letter of the alphabet twice. The speakers are grouped into sets of 30 speakers each [12]. TDT2: It is originally generated by NistTopic Detection and Tracking corpus and consists of data collected from 6 sources, including two newswires (APW, NYT), two radio programs (VOA, PRI) and two television programs (CNN, ABC). This database has 11201 on-topic documents which are classified into 96 semantic categories. In this subset, those documents appearing in two or more categories are removed, and only the largest 30 categories are kept, thus leaving us with 9394 documents in total [12]. 20Newsgroups: This data is organized into 20 different newsgroups, each corresponding to a different topic. Some of the newsgroups are very closely related to each other (e.g. comp.sys.ibm.pc.hardware/comp.sys.mac.hardware), while others are highly unrelated (e.g misc.forsale / soc.religion.christian) [12]. Here is a list of the 20 newsgroups, partitioned (more or less) according to subject matter as given in Table1.

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TABLE I: List Of The 20 Newsgroups, Partitioned According To Subject Matter comp.graphics comp.os.mswindows.misc comp.sys.ibm.pc.hardware comp.sys.mac.h-ardware comp.windows.x

rec.autos rec.motorcy-cles rec.sport.ba-seball rec.sport.ho-ckey

misc.forsale

talk.politics.misc talk.religion.misc talk.politics.guns alt.atheism talk.politics.mideast soc.religion.christian

sci.crypt sci.electronic-s sci.med sci.space

USPS: It is handwritten digit images database which contains 9298 documents [12]. Reuters21578: It contains 21578 documents in 135 categories. Those documents with multiple category labels are discarded. It left us with 8293 documents in 65 categories [12].

3.2.

Evaluation metric

The clustering results are evaluated by comparing the obtained label of each sample with the label provided by the data sets. Total three parameters are used to measure the clustering performance. These metrics are accuracy (AC) [13], mutual information (MI) [14] and time taken for execution. These are defined as: Where, ri and si are the obtained cluster label and the label provided by the given corpus, respectively. N is the total number of samples and  ( x, y) is the delta function that equals 1 if x=y and equals 0 otherwise. map(ri ) is the permutation mapping function that maps each cluster label ri to the equivalent label from the data corpus. Where, p(si ) and p(ri ) are the probabilities that a document arbitrarily selected from the corpus belongs to the clusters si and ri , respectively. p( si , ri ) is the joint probability that the arbitrarily selected document belongs to the clusters at the same time. The range of AC and MI is 0 to 1. It is one if two sets of clusters are identical, and 0 if the two sets are independent. In this study, the running time of each method is recorded in seconds. All the codes in the experiments are implemented in MATLAB R2014a and run on a HP desktop with 16GB RAM.

3.3.

Experimental Results

The performance of the seven methods along with seven real-world data sets are reported in Tables 2, 3, and 4. In this study same parameters are taken for all methods. These results give some interesting points as follows:  Considering the accuracy, LSC-K outperforms all of its competitors on all the data sets accepts 20Newsgroups and Reuters21578. LSC-K achieves approx 20% gain on MNIST dataset over the second best LSC-R method. In 20Newsgroups and Reuters21578 data set cases the LSC-K gives competent results. The reason might be the effectiveness of the landmark based sparse representation. However, the running time and mutual information results are its fatal weakness this may be due to the k-means based landmark selection.  GNMF-subspace method demonstrates an elegant balance between running time and accuracy while results are satisfactory between mutual information and estimated time. It runs much faster than the other six methods while achieves minimum accuracy. The overall performance is satisfactory in terms of MI and estimated time.  The differences among AC, MI and estimated time show that for any type real-world large scale data set for clustering, it is required to develop a universal framework for the representation and processing of knowledge. Human perceptual aspects must be incorporated into these methods.

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TABLE II: Accuracy

TABLE III: Mutual

TABLE IV : Elapsed

Information

Time (in seconds)

4. Conclusion In this paper, eight commonly used clustering algorithms are analyzed which is based on large scale data of eight different environment and dimensions to find out a universal framework for the representation and processing of knowledge. Our empirical study shows the encouraging accuracy results of the LSC-K outperforms all of its competitors on all the data sets accepts 20Newsgroups and Reuters21578. The results of mutual information and estimated time are not satisfactory for LSC-K method with accuracy. Hence, it is required to develop a universal framework for the representation and processing of knowledge for real-world large scale data set. Human perceptual aspects must be incorporated into the clustering systems.

5. References [1] A. K. Jain, M. N. Murty, and P. J. Flynn. Data clustering: a review. ACM Comput. Surv.1999. [2] J. Shi, and J. Malik. Normalized cuts and image segmentation. IEEE Transactions on Pattern Analysis and Machine Intelligence, 22(8): pages 888–905, 2000. [3] M. Filippone, F. Camastra, F. Masulli, and S. Rovetta. A survey of kernel and spectral methods for clustering. Pattern Recognition 41:176–190, 2008. [4] A. Y. Ng, M. I. Jordan, and Y. Weiss. On spectral clustering: analysis and an algorithm. In Advances in Neural Information Processing Systems 14. MIT Press, 2001. [5] F. R. K. Chung. Spectral Graph Theory, volume 92 of Regional Conference Series in Mathematics. AMS, 1997. [6] C. Fowlkes, S. Belongie, F. Chung, and J. Malik. Spectral grouping using the nystrom method.¨ IEEE Transactions on Pattern Analysis and Machine Intelligence 26:2004. [7] H. Shinnou, and M. Sasaki. Spectral clustering for a large data set by reducing the similarity matrix size. In Proceedings of the Sixth International Language Resources and Evaluation (LREC’08), 2008. [8] D. Yan, L. Huang, and M. I. Jordan. Fast approximate spectral clustering. In Proceedings of the 15th ACM International Conference on Knowledge Discovery and Data Mining (SIGKDD’09),2009. [9] T. Sakai and A. Imiya. Fast spectral clustering with random projection and sampling. In Proceedings of the 3rd International Conference on Machine Learning and Data Mining (MLDM’09), 2009. [10] B. Chen, B. Gao, T. Y. Liu, Y. F. Chen and W. –Y. Ma. Fast spectral clustering of data using sequential matrix compression. In Proceedings of the 17th European Conference on Machine Learning (ECML’06), 2006. [11] T. Y. Liu, H. Y. Yang, X. Zheng, T. Qin and W. –Y. Ma. Fast large-scale spectral clustering by sequential shrinkage optimization. In Proceedings of the 29th European Conference on IR research (ECIR’07), 2007. 4

[12] Deng Cai, Xiaofei He and Jiawei Han, "Document Clustering Using Locality Preserving Indexing", IEEE TKDE 2005. (http://www.cad.zju.edu.cn/home/dengcai/Data.html.) [13] Xinlei Chen and Deng Cai. Large scale spectral clustering with landmark-based representation. In Proc. of 25th AAAI. Pages 313-318, 2011. [14] Deng Cai, Xiaofei He, Jiawei Han, and Thomas S. Huang. Graph regularized nonnegative matrix factorization for data representation. IEEE Trans. On Pattern Analysis and Machine Intelligence, 33:8, 2011.

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Comparison of Four Different Methods of the Ant Colony Optimization Algorithm Applied to Crew Dispatch for Network Services in an Electricity Utility Paulo Baumann1, Tiago Miranda1, Fabio Romero1, João Castilho Neto 1, Alden Antunes1, Dário Takahata1, Leonardo Ferreira Neto1, Angelo Alves2, Luisa Azevedo2, Sérgio Valinho2. 1

Daimon Engineering & Systems Energy Company of Maranhão

2

Abstract: This paper shows the application of Ant Colony Optimization for the dispatch of crew teams for service assistance in an electricity utility. Four variations of the optimization algorithm are tested: sequential, deterministic-concurrent, random-concurrent and simultaneous. The methodology takes as input a set of service calls and the importance of assisting each of them. The algorithm is able to create the routes to be taken by each team and the sequence in which the services will be assisted taking into account the benefits of assisting a certain service as well as the impact of not assisting it. A computer program was developed to apply these methods and the results were considered better than the ones from the current methods used by the Company. Also, it is more suitable for real time daily applications. Finally, the four variations are compared. Keywords: Ant colony optimization, crew dispatch, service assistance.

1. Introduction The study presented on this paper is part of a Research and Development (R&D) Project of ANEEL (Brazilian Electricity Regulatory Agency), developed jointly by Electricity Company of Maranhão (CEMAR) and Daimon Engineering & Systems. CEMAR is a private-owned electric distribution utility, located in the northern region of Brazil which supplies over 2,000,000 customers, in the state of Maranhão, in Brazil. Currently, at CEMAR (and at many other Brazilian electric companies), just a few variables are taken into account by the Company’s dispatchers when service assistance is needed. They make their decisions based on previous knowledge, usually intuitively or by ad hoc methods. Also, the decisions are not reevaluated even if the circumstances are different. In order to select the services to be assisted, its sequence and the route to be taken by each available team, a consolidated meta-heuristic method was implemented: The Ant Colony Optimization (ACO) algorithm. Four variations of it were implemented and compared: sequential, deterministic-concurrent, random-concurrent and simultaneous [1]. The product developed offers to CEMAR and also to the technical community and to the society some important solutions and tools that are not yet contemplated by the current systems, making it an original project. It is a sophisticated tool that makes the most suitable decision for crew dispatch. This paper is organized in a way that the next section presents the theoretic bases of the project, the ACO meta-heuristic method. On Section III, the methodology is described. Section IV shows and discusses the results and, finally, Section V concludes the paper.

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2. Ant Colony Optimization The Ant Colony Optimization (ACO) belongs to a meta-heuristic group based on populations. This method can be used to solve the crew dispatch problem, in which there is a set of places to be visited and, in each of them, there is a prize to be taken by the visiting team. Once a team arrived at the point and receives the prize, no other team can receive it. The goal is to maximize the total prize [1]. This technique was inspired by the fact that ants from a colony guide themselves by a track of pheromones, searching for the best path to their food source. Good tracks are chosen more often, making its pheromone concentration greater as well as the likelihood of it being chosen again. However, some ants can explore other possibilities trying to find paths that are even better [1]. The problem can be presented as a graph. The service locations are the vertices and the paths are the edges. In ACO algorithms, an ant represents a solution. When constructing a solution, each ant is put on a starting point and then wanders randomly from vertex to vertex in the graph. At each vertex, an ant probabilistically selects the next vertex according to a decision policy or transition rule, which depends on the pheromone trails and on the heuristic information on the edges and vertices. Also, they deposit pheromone in the edges in order to attract other ants towards the corresponding area of the search space. The pheromones can evaporate, allowing some past history to be forgotten, and helping diversify the search to new and hopefully more promising areas of the search space [1]. During the construction of a solution, an ant chooses a feasible path for each vehicle (a crew team). The choice method depends on the variation of the ACO algorithm to be used. There are four variations: sequential, deterministic-concurrent, random-concurrent and simultaneous [1]. A. Sequential In this case, firstly an ant chooses a vehicle and selects a path for it according to the pheromone tracks and the heurist. A different vehicle will only be taken when there are no more feasible vertices to be visited by the first one [1]. B. Deterministic-Concurrent In this situation, after choosing a vehicle-vertex pair (according to the pheromone tracks and the heuristic), an ant can take another vehicle. The vehicle choosing procedure is deterministic, which means the sequence of the vehicles is previously fixed. For each vehicle, the feasible vertices are identified and one is chosen according to its likelihood. Then, the next vehicle is selected and the procedure continues until there are no more feasible vertices for a vehicle [1]. C. Random-Concurrent This case is very similar to the deterministic-concurrent. The only difference is the procedure in which the vehicles are chosen. Here, the next vehicle is randomly chosen [1]. D. Simultaneous At first, all the feasible vehicle-vertex pairs are considered. Then, the probability of each pair is calculated according to the pheromone tracks and the heuristic. Thus, one of these pairs is chosen respecting its probability. After, the problem constraints are verified and the set of vehicle-vertex pairs are updated. The process goes on until there are no more feasible pairs [1]. For all the cases, a fixed number of ants/solutions is predefined within a cycle (the amount of cycles is also defined previously). A solution consists of a set of routes, one for each vehicle/team. In a cycle, all ants independently try to find the better routes for the vehicles. In the next cycle, its ants will be influenced by the pheromones left by the ones from the previous cycles. At the end of the process, the solution that maximizes the prize is chosen [1].

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3. Methodology A. The System The system’s goal is to attribute the service calls (SCs) to the most suitable available crew teams taking into account the benefits of assisting a certain service as well as the impact of not assisting it. The attribution must take into account some parameters. They are: the execution average time by service and by team, team location, acting area, expected travel time, maximum and minimum Standard Service Unities (SSUs – it is a time unity used to measure the duration of service assistance of the team crews, varying from team to team according to the average travel time in its acting area) to be accomplished, team shift duration, availability, connectivity, vehicle type, vehicle traction type and team costs matrix. The characteristics of the region assisted by CEMAR and of the Brazilian electricity system require some rules that must be considered by the dispatch system. They are:  Team dispatch for supply interruption services due to non-payment must occur at a pre-defined time or as close to this as possible, if not possible;  Services that are manually assigned to a team must me assisted first;  No service can interfere in another that is currently being assisted;  Supply interruption services due to non-payment must be done until a pre-defined time. The SCs that cannot be assisted by that time will be placed at the end of the route. However, for route construction and solution comparison it is considered they will not be assisted;  Each team must assist a minimum and a maximum of SSUs;  The feasibility of the assistance of a SC by a team is defined in the price book (a table that defines the assisting costs by service type, crew team and area) or in the team’s parameters;  Temporary new connections cannot be done before 1 hour of the scheduled time;  Temporally connections must occur between 1 hour before the scheduled time and the schedule time;  Crew teams can change vehicles just in case of accident or bad operation. In this case, the team will be set as non-available, the dispatch manager will close its shift e then will initiate a new shift with the associated new vehicle;  SCs whose opening reason is in a pre-defined list will not be assigned by the system. The operator will do it manually;  The cutoff location must be evaluated when dispatching teams for reconnection services;  An increment on the cost matrix must be considered when teams with no traction vehicles assist services in country areas;  Supply interruption services due to non-payment can be allocated in a group according to their coordinates and types and will be assisted by one team only;  A regional possess many operational base that can assist many towns or part of a city. Teams can assist all the operational base extension, but they should be dispatched preferentially to where they have more experience;  Solutions in which a team could not achieve its production target must not be considered;  The standard service duration, measured in SSU, varies according to service, team and regional;  Temporary cutoff must be done after the scheduled time;  The lunch break duration is of 2 hours, from 12pm to 2pm;  Commercial SCs can be assisted at any time;  A SC must be located in the team acting area;  The team must be able to assist the SC (according to its cost matrix);  The team must be available;  The team must be able to receive messages from the operator, and; 8



The vehicle used by the team must suit the SC.

In order to estimate the time to be spent by a team for the assistance of the assigned SCs and make sure it can start assisting the last SC before the end of the shift, it is necessary to measure the assistance duration and travel time. The assistance duration will be estimated by the average time spent by the team in that type of service. The distances and travel times between SCs are calculated using mapping web tools, like Google Maps. Alternatively, the linear distance between the coordinates and the average speed can be used to calculate the travel time. The system assumes the existence of a previous system able to define the SC’s importance. Also, in some days, there will be SCs that will not be assisted. Knowing that, the most important SCs should be assisted preferentially. B. The Solution A solution is valid if it defines a set of routes containing the SCs to be assisted by a team observing the previously mentioned rules. The best solution will be the one that minimizes the sum of the importance of the non-assisted SCs (X) and minimizes the sum of the assisted SCs (Y) respectively. These values will be presented in the next section in separated brackets like this: [X | Y]. The lexicographic method will be used here. In this method, capable of finding an optimal solution, it is given maximum importance to the first target (minimizing the sum of the importance of the non-assisted SCs). In case just one solution is found when minimizing the first function, it is chosen and the other targets are not evaluated. In case there are multiple solutions, the next step is to minimize the second most important target. From the second minimization, a new constraint is considered to make sure the value from the previous target does not increase [2].

4. Results Two fictitious and simplified situations have been proposed in order to illustrate the results that can be obtained by the new methodology. In all of them some SCs were created in order to be met by 3 crew teams. The SCs have been prioritized previously and an index was calculated to measure the effectiveness of the solutions. The SCs are divided in three types as follows: a) Supply interruption services due to non-payment: Disconnection procedures applied to the customers who failed to pay the electricity bills; b) Commercial services: These are service orders requested by the consumers for instance, to check their meters, do new connections, do reconnection after paying their debts etc.; c) Supply restoration services: These are technical service orders, primarily to reestablish energy supply after a fault. In short, emergency orders have to do with disconnection of customers and safety issues; d) The first situation will focus on comparing the current method to the new one with its 4 possible variations. The second one will compare just the 4 ACO algorithms in order to explore the limitations of each of them. A. First Situation The first situation was created in order to compare the current method applied by CEMAR (basically intuitive with very simple restrictions) with the 4 ACO variations. Thirty-six SCs have been created and the 3 crew teams have the same characteristics and an 8 hours shift. The characteristics of each SC are specified on Tables I, II and III:

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TABLE I: List of pending supply interruption services Supply interruption services due to non-payment 01 02 03 04 05 06 07 08 09 10 11 12

Customer´s accumulated debt (US$) 200.00 200.00 200.00 200.00 1,000.00 1,000.00 1,000.00 1,000.00 5,000.00 5,000.00 5,000.00 10,000.00

Process started before dispatch (hours) (1) 24 24 18 96 24 24 24 18 24 24 24 24

(1) Dispatch time: 09:00 a.m. on December 5th 2015

TABLE II: List of pending commercial services Commercial services (all reconnection) 13 14 15 16 17 18 19 20 21 22 23 24

Client importance (1)

Type of request

S S S S S P P P S S S S

Client´s average bill (US$)

Ordinary Ordinary Ordinary Judicial Ordinary Ordinary Judicial Judicial Ordinary Ordinary Ordinary Judicial

5,000.00 5,000.00 5,000.00 5,000.00 5,000.00 5,000.00 5,000.00 15,000.00 15,000.00 15,000.00 500.00 500.00

Process started (hours) (2)

Deadline (hours)

24 before 3 after 6 after 18 before 24 before 3 after 18 before 24 before 24 before 6 after 24 before 24 before

8 32 32 32 8 32 32 32 32 32 8 32

TABLE III: List of pending supply restoration services. Supply restoration services

Clients importance (2)

Complaints (1)

Recalls (3 )

Reincidences (4)

Process started before dispatch (5) (hours)

25 P G 15 0 26 P G 10 2 27 P G 10 0 28 G S 5 5 29 S G 5 3 30 T I 0 5 31 T I 0 0 32 S I 0 0 33 S I 0 0 34 S I 0 0 35 T I 0 0 36 T I 0 0 (1) I – Individual request; G – Group of consumers request. (2) P – Primary; S – Secondary; T – Tertiary. (3) Number of telephone calls from the same client. (4) Number of times that the same fault ocurred within, for instance, a month. (5) Dispatch time: 09:00 a.m. on December 5th 2015.

2 2 2 24 24 24 24 0 19 17 0 0

One should stress that supply interruption services due to non-payment do not cause any kind of regulatory penalty to the utility by not meeting some kind of standard, because in Brazil there is no standard regarding shutoff clients. It is up to the utility to reduce the amount of pending electricity bills, in order to diminish its commercial losses. So the utility usually prioritizes the customers who have greatest total debit.

10

How quick the commercial services should be assisted depends on the importance of the client to the utility as well, according to the classification index. Primary importance means that this type of customer is the most important one to the utility, followed by the secondary client and by the tertiary one. The supply restoration services must usually be assisted as soon as possible, mainly if it affects a large number of customers. For this study it was considered that the time spent to assist a supply interruption services due to nonpayment is 30 minutes. For the other services the time spent is 1 hour. Thus, the fictitious situation was given to CEMAR’s dispatch operator so he could dispatch the crew teams in order to meet the SCs using the current method. The result obtained is shown on Table IV. TABLE IV: Dispatch made by the Company’s Operator SC sequence

Team 1

Team 2

Team 3

1 2 3 4 5 6 7 8 9 10 11

06 08 10 09 15 28 25 27 13 22

04 02 01 05 03 24 33 31 29 12 34

16 07 26 17 19 18 21 20 11

Unattended SCs: 14, 23, 30, 32, 35 and 36

As predicted, CEMAR’s solution has some problems, once it was intuitively built and could not take into account all the problem’s constraints. In this example, the dispatcher did not consider the displacement time, so it would not be possible to meet all the SCs pointed out. Also, he forgot that SC 15 could only be met at 3 p.m. and tried to meet it earlier. In order to measure the effectiveness of CEMAR’s solution, its dispatch was simulated by the new algorithm for comparison. The simulation, however, took into account the crew teams shift duration and all the other constraints. In the new result, the SCs 11, 13, 22, 25 and 27 could not be met as well as the other SCs unattended by the previous solution. The final score of the solution was [852.04 | 3045.09]. The other algorithms presented similar solutions among them but very different from the current method. The final score calculated for the solution using the sequential, deterministic-concurrent, random-concurrent and simultaneous are respectively: [258.84 | 3621.93], [275.98 | 3603.69], [258.84 | 36017.52] and [258.84 | 30618.62]. Thus, the solutions proposed by the project were able to better achieve the company’s goals. Fig. 1 is a graph showing the scores of each algorithm and CEMAR throughout the day. One can see that the algorithms solutions presented best scores all day long.

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Fig.1: On the top unattended SCs (work orders) scores throughout the day; On the bottom visited SCs (work orders) scores throughout the day. “Seq” refers to sequential, “det” refers to deterministic-concurrent, “ran” refers to random-concurrent and “sim” refers to simultaneous.

B. Second Situation This situation will focus on exploring possible limitations of the 4 ACO variations. In this case, the crew teams are not equal. Now, team 1 is much faster than team 2 and 3. All of them have a 24 hours shift. Also, just 3 SCs were created. They are described on Table V and VI. TABLE V: Pending commercial services Commercial Services (all reconnection) 01 02



Type of request

Process started (2) (hours)

S

Ordinary

5,000.00

1 before

S

Ordinary

5,000.00

1 before

Deadline (hours) 0 0

(1) P – Primary; S – Secondary; T - Tertiary (2) Dispatch time: 09:00 a.m. on December 5th 2015

TABLE VI: Pending supply restoration service. Supply restoration services 03

Clients importance (1) P

Complaints (2) G

Recalls (3) 10

Reincidences (4) 0

Process started before dispatch (5) (hours) 2

( ) P – Primary; S – Secondary; T - Tertiary. (2) I – Individual request; G – Group of consumers request. (3) Number of telephone calls from the same client. (4) Number of times that the same fault ocurred within, for instance, a month. (5) Dispatch time: 09:00 a.m. on December 5th 2015. 1

For the sequential algorithm the result is very dependent on the crew team selection. In case team 1 is selected, the solution is very good because the fast team 1 will assist to all the SCs at a good speed and the final score will be good. However, if instead of it, 2 or 3 were selected, the result would be much worse. Another disadvantage is that this algorithm left two teams resting while just one worked. When using the deterministic-concurrent algorithm, the limitation is caused by having to set a sequence in which the teams will be chosen. In some cases, the team of the turn is not the most suitable for the SCs left at that time and you have no choice but use it. The problem with the random-deterministic algorithm is similar. The difference is that the teams sequence is randomly set.

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At last, the simultaneous algorithm seemed to be the most adaptive because it makes possible to choose the most suitable feasible team-SC pair that can be chosen at each time. The disadvantage of this method is a consequence of its adaptiveness: once it has to calculate the feasible team-SC pairs for all the available teams, it spends a larger computational processing time.

5. Conclusion Dispatching crew teams is a very hard work, once it has to take into account the changing circumstances and the many possible variables. But at the same time it has great importance in keeping the electricity systems working. Thus, this paper proposes to present a new method for automatic crew team dispatch in an electricity utility. It was based on the Ant Colony Optimization (ACO) algorithm, which has 4 variations: sequential, deterministic-concurrent, random-concurrent and simultaneous. First of all, the 4 algorithms were compared to the current method used by the company (basically intuitively). All of them could achieve better the goals of the utility. At last, the 4 ACO algorithms were implemented in a situation that would test their limitations. The sequential algorithm does not work well in cases in which a slower team is chosen to assist a set of service calls (SCs) while some faster teams are assigned to none. The concurrent methods showed similar problems between each other. In both cases, once a team is chosen, according to a defined sequence or randomly, the best feasible team-SC pair might not be chosen which would not lead to the best solution. Finally, the simultaneous case seemed to be the most adaptive one, because it considers, at each chance, all the feasible team-SC pairs and can choose the best one. However, it is consequently the one that spends more computational processing time.

6. References [1] [2]

Ke, Liangjun; Archetti, C.; Feng, Z. “Ants can solve the team orienteering problem.” Computers & Industrial Engineering, v. 54, n. 3, 2008, pp. 648–665. Denis Bouyssou, Thierry Marchant, Marc Pirlot, Alexis Tsoukiàs, Philippe Vincke. “The lexicographic method,” in Evaluation and decision models with multiple criteria: Stepping stones for the analyst, v. 86. [S.I.]: Springer Science & Business Media, 2006, pp. 188-190.

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Crew Dispatch for Network Services in an Electricity Utility Using Ant Colony Optimization Methodology Paulo Baumann1, Tiago Miranda1, Fabio Romero1, João Castilho Neto 1, Alden Antunes1, Dário Takahata1, Leonardo Ferreira Neto1, Angelo Alves2, Luisa Azevedo2, Sérgio Valinho2. 1

Daimon Engineering & Systems Energy Company of Maranhão

2

Abstract: This paper presents an application of the Ant Colony Optimization methodology for the dispatch of field crews for realizing work orders in an electricity utility. The methodology takes as input a set of service calls and the importance of meeting each of them. The algorithm is able to create the routes to be taken by each team and the sequence in which they will be met taking into account the benefits of meeting a certain work order as well as the impact of not meeting it. This study is of great relevance and complexity because it dynamically optimizes the use of the potential capacity of the available crew, increasing their efficiency and enabling the Company to be prepared to unpredictable situations. A computer programme has been developed to apply this method and the results have been considered better than the ones from the current methods used by the Company and from others available on the literature. Also, it is more suitable for real time daily applications.

Keywords: ant colony optimization; commercial and technical work orders; crew dispatch; real-time assignments.

1. Introduction The study presented presented on this paper is part of a Research and Development (R&D) Project of ANEEL (Brazilian Electricity Regulatory Agency), developed jointly by Maranhão Electricity Company (CEMAR) and Daimon Engineering & Systems. CEMAR is a private-owned electric distribution utility, located in the northern region of Brazil which supplies over 2,000,000 customers, in the state of Maranhão, in Brazil. Currently, at CEMAR (and at many other Brazilian electric utilities), just a few variables are taken into account by the utility’s dispatchers when the assignment of work order is needed. They make their decisions based on previous knowledge, usually intuitively or by ad hoc methods. Also, the decisions are not re-evaluated even if the circumstances are different. One should point out that the computer tool called ANTECOM (Ant Colony Tool for Prioritizing and Dispatching Technical and Commercial Work Orders) comprises two different modules: The former uses the Macbeth (Measuring Attractiveness by a Categorical Based Evaluation Technique) approach, which is a multicriteria decision method [1] for the prioritization of commercial and supply restoration services in an electricity company. The latter is the content of the present paper, which uses the Ant Colony Optimization (ACO) methodology [2], in order to assign the services to be met, its sequence and the route to be taken by each available field crew. Brazilian distribution companies are obliged to meet some quality of service standards, as from the commercial standpoint, as from the technical one. If they fail to meet the level of service required, then customers may be entitled to a payment. In the case of technical services, for instance, the amount paid to customers depends on many factors, such as the cause of the interruption, the accumulated number of times

14

within a certain month, in which the supply has been interrupted, and the amount of time the supply has been interrupted.

2. Objectives This paper presents a methodology and its correspondent computer programme based on concepts of Ant Colony Optimization methodology which will yield a real-time assignment list of available field crews to meet services demanded by consumers from telephone calls (as commercial as technical work orders) in a real-time basis. The goal is to meet several criteria simultaneously, forming a multi-objective problem, on which there is a compromising solution to meet commercial and technical issues, besides meeting less tangible issues, such as damage to the utility´s image. Amongst the tangible goals, one can quote: a) Reduce the payments realized from CEMAR to its customers for not meeting technical standards [3] and commercial ones [4]; b) Meet CEMAR´s variables which have been considered relevant according to their importance level, as follows:  Commercial Standards: Client importance, compensation for violating the time duration of commercial standard, complaint origin, meeting rate within pre-established time in order to meet the monthly standard, meeting rate within pre-established time in order to meet the annual standard, commercial service meeting rate in order to meet the monthly production standard, and commercial service meeting rate in order to meet the annual production standard;  Technical Standards: Monthly SAIDI, annual SAIDI, compensation for violating individual reliability standards, reason for starting the complaint, client importance, number of recalls, number of reincidences; and remaining time to violate 24-hour deadline.

3. Ant Colony Optimization The Ant Colony Optimization (ACO) belongs to a meta-heuristic group based on populations. This method can be used to solve the crew dispatch problem, in which there is a set of places to be visited and, in each of them, there is a prize to be taken by the visiting team (in this case, the prize is a work order). Once a team arrived at the point and received the prize, no other team can receive it. The goal is to maximize the total prize. This technique has been inspired by the fact that ants from a colony guide themselves by a trail of pheromones, searching for the best path to their food source. Good trails are chosen more often, making its pheromone concentration greater as well as the likelihood of it being chosen again. However, some ants can explore other possibilities, trying to find paths that are even better than the previous ones. The problem can be presented as a graph. The work locations are the vertices and the paths are the edges. In ACO algorithms, an ant represents a solution. When constructing a solution, each ant is put on a starting point and then wanders randomly from vertex to vertex in the graph. At each vertex, an ant probabilistically selects the next vertex according to a decision policy or transition rule, which depends on the pheromone trails and on the heuristic information on the edges. Also, they deposit pheromone in the edges in order to attract other ants towards the corresponding area of the search space. The pheromones can evaporate, allowing some past history to be forgotten, and helping diversify the search to new and hopefully more promising areas of the search space. During the construction of a solution, an ant chooses a feasible path for each vehicle (a field crew). The choice method depends on the variation of the ACO algorithm to be used. There are four variations: sequential, deterministic-concurrent, random-concurrent and simultaneous. For the simultaneous case, applied to this research, at first, all the possible vehicle-vertex pairs are considered. Then, the probability of each pair is calculated according to the pheromone trails and the heuristic information. Thus, one of these pairs is chosen respecting its probability. Subsequently, the problem constraints are verified and the set of vehicle-vertex pairs are updated. The process goes on until there is no more possible pairs. 15

A fixed number of ants/solutions is predefined within a cycle (the amount of cycles is also defined previously). A solution consists of a set of routes, one for each vehicle/team. In a cycle, all ants independently try to find the better routes for the vehicles. In the next cycle, the ants will be influenced by the pheromones left by the ones from the previous cycles. At the end of the process, the solution that maximizes the prize is chosen.

4. Methodology A. The System The goal of a dispatch centre is to assign the work orders (WOs) to the most suitable road crew taking into account the benefits of meeting a certain service as well as the impact of not meeting it. The attribution should consider the execution average time by service and by team, team location, acting area, expected travel time, maximum and minimum Standard Service Unities (SSUs – it is a time unity used to quantify the duration of realized work of the field crews, varying from team to team according to the average travel time in its acting area) to be accomplished, team shift duration, availability, connectivity, vehicle type, vehicle traction type and team costs matrix. The characteristics of the region met by CEMAR and due to the set of Brazilian regulation laws of the electricity system require some rules that must be considered by the dispatch system. The main rules are presented as follows:  Crew dispatch for shut-off works due to non-payment bills must start at 7:00 am or as close to it as possible; and these shut-off works must be done before 4:00 pm;  Shut-off work orders will not be assigned by the dispatch system. The dispatch manager does it manually;  Works that are manually assigned to a certain crew must be met firstly;  No work order may interfere in another one that is currently being met;  Shut-off works due to non-payment must be done before 4:00 pm;  The shut-off location (pole, meter, secondary network) should be evaluated when dispatching crews for reconnection services;  Each crew must meet a minimum and a maximum number of SSUs. Violations above the maximum limit are tolerated;  Solutions of which a field crew could not achieve its production target must not be considered;  The standard service duration, measured in SSU, varies according to service, team and Regional Agency;  The lunch break duration is of 2 hours;  Commercial WOs can be realized at any working time;  A work order must be located in the team acting area;  The crew must be able to receive messages from the operation manager;  The vehicle used by the crew must suit the WO;  The WO can only be assigned to a team if there is enough time of it to be met before its shift ends. In order to estimate the time to be spent by a team to meet the assigned WOs and make sure they can be realized before the end of the shift, it is necessary to measure the assistance duration and travel time. The assistance duration will be estimated by the average time spent by the team in that type of service. The distances and travel times between WOs are calculated using mapping web tools, like Google Maps. Alternatively, the linear distance between the coordinates and the average speed can be used to calculate the travel time. The system assumes the existence of a previous system able to define the SC’s importance and that the importance of each of them can vary through time. Also, in some days, there will be WOs that cannot be assisted. Knowing that, the most important WOs should be met preferably.

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The work orders (WOs) in this study comprise 3 different types of services carried out by the road crews, and their characteristics are briefly explained as follows: a) Shut-off orders: Disconnection procedures applied to the customers who failed to pay the electricity bills. These orders are scheduled at the night before and should be accomplished in the morning of the next day, starting preferably at 07:00 a.m., before the other type of orders; b) Commercial orders: These are service orders requested by the consumers for instance, to check their meters, realize new connections, realize reconnection after paying their debts, etc. These services are accomplished during the time band of working days (if the commercial standard is in working days) or hours (if the commercial standard is in hours, like, for instance, a judicial reconnection, whose deadline is within 4 hours); c) Emergency orders: These are technical service orders, primarily to reestablish energy supply after a fault and are opened around the clock. One should point out that voltage complaints, although having a technical character, according to Brazilian legislation, belong to the previous item. In short, emergency orders have to do with disconnection of customers and safety issues and may be accomplished at any time.

B. The Solution A solution is valid if it defines a set of routes containing the WO´s to be met by a crew observing the previously mentioned constraints. The best solution will be the one that minimizes the sum of the importance of the non-assisted WOs and minimizes the sum of the assisted WOs, ordered by preference. The lexicographic method will be used here. In this method, capable of finding an optimal solution, it is given maximum importance to the first target. In case just one solution is found when minimizing the first function, it is chosen and the other targets are not evaluated. In case there are multiple solutions, the next step is to minimize the second most important target and so on. From the second minimization, a new constraint is considered to make sure the value from the previous target does not increase [5]. However, due to possible inaccuracies on the importance classification, two parameters varying to ±10% are considered equal when comparing solutions and then the next target is evaluated.

5. Results A fictitious and simplified situation has been proposed in order to illustrate the results that can be obtained by the new methodology. Thus, 36 WOs have been created and prioritized according to the company’s interests and the final score of each solution to be presented next was calculated based on it. The dispatch algorithm has been applied to this example. Also, the current dispatch method (mainly intuitively) has been applied by CEMAR’s operator in order to make a comparison of the two methods. Fig. 1 present a map of São Luis with 36 pending WOs which should be assigned to 3 road crews on December 5th 1915 at 09:00 a.m. across the city of São Luis, in Maranhão, Brazil, as if these WOs were in a real-time environment within CEMAR´s Dispatch Centre. The current method used nowadays by CEMAR is basically intuitive with very simple restrictions, like avoiding the presence of crews in the same acting region.

17

Fig. 1: Map of São Luis with 36 Pending Work Orders.

According to Fig. 1, the red balloons represent the emergency work orders, the yellow ones represent the commercial work orders, the green ones represent shut-off work orders and finally, and the grey balloons represent the road crews, located at 09:00 a.m. on December 5th 1915, on the streets of São Luis, in Maranhão. Therefore, as one can see on Fig. 1, the algorithm has to find out an optimized solution in order to meet these 36 pending WOs through the 3 field crews as quickly as possible Table 1 presents a list of the pending Shut-off Work Orders which appears on the screen of CEMAR´s OPER (Electric Distribution System Operational Management) at 09:00 am. One should stress that the shut-off work orders do not cause any kind of regulatory penalty to the utility by not meeting some kind of standard, because in Brazil there is no standard regarding shut-off clients. It is up to the utility to reduce the amount of pending electricity bills, in order to diminish its commercial losses. TABLE I: List of Pending Shut-Off Work Orders. Shut-off Work Order (SWO)

Customer´s accumulated Debt (US$)

Process started before dispatch (hours) (1)

01 02 03 04 05 06 07 08 09 10 11

200.00 200.00 200.00 200.00 1,000.00 1,000.00 1,000.00 1,000.00 5,000.00 5,000.00 5,000.00

24 24 18 96 24 24 24 18 24 24 24

12

10,000.00

24

(1) Dispatch time: 09:00 a.m. on December 5th 1915

Table 2 presents a list of the pending Commercial Orders which appears on the screen of CEMAR´s OPER, at the same time of the day as the Table 1. How quick the commercial work orders should be assisted depends on the importance of the client to the utility as well, according to the classification index. Primary importance means that this type of customer is the most important one to the utility, followed by the secondary client and by the tertiary one. Additionally, how the work order has been tagged by the utility´s Call-Centre or reception desk is also relevant. The consumer request may be started as an ordinary order via telephone call into the Call-Centre (the

18

majority of cases), or sometimes, via court order through a judge, who demands the customer to be reconnected within a certain time period. TABLE II: List of Pending Comercial Work Orders Commerci-al Work Order (CWO)


Process started (2) (hours)

Deadline (hours)

01 S Ordinary 5,000.00 02 S Ordinary 5,000.00 03 S Ordinary 5,000.00 04 S Judicial 5,000.00 05 S Ordinary 5,000.00 06 P Ordinary 5,000.00 07 P Judicial 5,000.00 08 P Judicial 15,000.00 09 S Ordinary 15,000.00 10 S Ordinary 15,000.00 11 S Ordinary 500.00 12 S Judicial 500.00 (1) P – Primary; S – Secondary; T - Tertiary (2) Dispatch time: 09:00 a.m. on December 5th 1915

24 before 3 after 6 after 18 before 24 before 3 after 18 before 24 before 24 before 6 after 24 before 24 before

8 32 32 32 8 32 32 32 32 32 8 32


Type of request

Table 3 presents a list of the pending Emergency Work Orders which appears on the screen of CEMAR´s OPER, at the same time of the day as the Table 1 and 2. Thus, the challenge of ANTECOM is to optimize the route of the 3 road crews in order to meet these 36 pending WO´s at 09:00 a.m. on December 5th 1915, considering their characteristics and their respective impact by prioritizing a few orders in detriment of others, and also pondering the possibility of not meeting some of them. TABLE III: List of Pending Emergency Work Orders Emergency Work Order (EWO)

Clients importance (2)

Complaints (1)

Recalls (3 )

Reincidences (4)

01 P G 15 0 02 P G 10 2 03 P G 10 0 04 S G 5 5 05 S G 5 3 06 T I 0 5 07 T I 0 0 08 S I 0 0 09 S I 0 0 10 S I 0 0 11 T I 0 0 12 T I 0 0 (1) I – Individual request; G – Group of consumers reques.t (2) P – Primary; S – Secondary; T – Tertiary. (3) Number of telephone calls from the same client. (4) Number of times that the same fault ocurred within, for instance, a month. (5) Dispatch time: 09:00 a.m. on December 5th 1915.

Process started before dispatch (5) (hours) 2 2 2 24 24 24 24 0 19 17 0 0

A. CEMAR´s Crews Trajectories In order to compare the performances of ANTECOM and the method currently used by CEMARS´s dispatchers, Figs. 2 - 4 show the trajectories of the 3 road crews (grey balls of Fig. 1), initially located on the streets of São Luis, in Maranhão at 09:00 a.m. on December 5th 1915. From then on, each crew visited the work orders according to the instructions of the Dispatch Centre of CEMAR, as shown on Table IV.

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Fig. 2. Trajectory of the #37 road crew, from 09:00 am onwards



TABLE IV: List of Work Assignments to Field Crews Dispatched by CEMAR Work Order Sequence 1 2 3 4 5 6 7 8 9 10 11 Labour hours

Road Crew # 37

# 38

# 39

S06 S08 S10 S09 C03 E04 E01 E03 C01 C10

S04 S02 S01 S05 S03 C12 E09 E07 E05 S12 E10 8

C04 S07 E02 C05 C07 C06 C09 C08 S11

8

8

As one can see by Table IV, # 37 road crew starts at 09:00 am heading towards the location of S06 work order, and after finishing its job, goes to the next work order (S08), and so on, successively, until its last work order of the day (C10). The same procedure happens to the other 2 road crews. The Figs. 2 – 4 show the trajectory of # 37, # 38 and # 39 road crews, respectively, from 09:00 am onwards. As predicted, CEMAR’s solution has some inaccuracies, once it has been intuitively built and could not take into account all the problem’s constraints. In this example, the dispatcher has not considered the displacement time, so it would not be possible to meet all the work orders pointed by them. Also, he has forgotten that WO C03 could only be met at 3 pm onwards, nonetheless tried to meet it earlier.

20

In order to measure the effectiveness of CEMAR´s solution, its dispatch was simulated by ANTECOM’s for solution comparison. The simulation, however, took into account the road crews shift duration and all the other constraints. In the new result, the WOs E01, E03, C01, C10 and S11 could not be met as well as the other WOs unattended by the previous solution. The final score of non-assisted WOs of the solution was 852.04 (the higher the score, the worse is the solution). B. CEMAR´s Crews Trajectories Table V shows the WO met by each road crew according to ANTECOM’s dispatch. Figs. 5 to 7 show the trajectory of # 37, # 38 and # 39 road crews, respectively, from 09:00 am. onwards. Comparing both solutions, it is possible to notice that CEMAR tried to minimize the routes to be taken and the work orders importance seemed to be less explored, while ANTECOM’s approach was able to make the company’s interests more relevant to the solution. The final score of non-assisted WO´s of ANTECOM’s solution is 258.84, an improvement of 229%. TABLE V: List of Work Assignments to Field Crews Dispatched by ANTECOM Work Order Sequence 1 2 3 4 5 6 7 8 9 10 Labour hours

Road Crew # 37

# 38

# 39

S12 S11 C08 C06 C07 E10 E06

S09 E03 C12 S04 S01 S02 S05 S03 E04 S08 8

S10 E02 E09 E01 E05 C04 S07 S06

8


8


Fig. 7 Trajectory of the #38 road crew, from 9:00 am onwards

Fig. 8 Non-visited WO´s score throughout the day 21

Fig. 8 shows a graph of the scores of non-assisted WOs of both CEMAR and ANTECOM dispatch throughout the day. One can see that ANTECOM presented the best score all day long.

6. Conclusion Dispatching field crews is a nonstop process, compelled by the arrival of new work orders, weather conditions, loss of connectivity etc. It is a very hard work to the Dispatch Centre to keep the electric systems working, taking into account the changing circumstances. ANTECOM is a tool to help the utility to face this task, providing an optimized way to prioritize and assign the work orders to the available road crew. The latter is the subject of this paper, using the Ant Colony Optimization (ACO) methodology, providing an optimized work orders sequence and routes to be taken by each available field crew. According to the simulated merit indexes, the solution score of CEMAR´s unattended WOs was 852.04, whereas ANTECOM´s score was 258.8. The former reflected the decisions made by CEMAR´s dispatchers based on previous knowledge, intuition and experience, which also may present an inaccurate response due to the real-time amount of information and pressure. The latter implemented the simultaneous ACO algorithm to optimize the result according to the number of field crews available and to the company’s main goals. The product developed offers to CEMAR, to the technical community and to society an important tool that is not yet contemplated by the current systems. Also, by its capacity to evaluate – in a totally automatic way - all the variables considered relevant by the company in real time and dynamically, the product is a sophisticated tool.

7. References [1]

[2] [3] [4] [5]

Bana e Costa, C. A.; Corte, J. M.; Vansnick, J. C. “On the mathematical foundation of MACBETH.” In: Figueira, Jose, Greco, Salvatore and Ehrgott, Matthias, (eds.) Multiple Criteria Decision Analysis: the State of the Art Surveys. International series in operations research & management science. Springer, New York, USA, pp. 409-442. ISBN 038723067X, 2005. Ke, Liangjun; Archetti, C.; Feng, Z. “Ants can solve the team orienteering problem.” Computers & Industrial Engineering, v. 54, n. 3, 2008, pp. 648–665. ANEEL (Brazilian Electricity Regulatory Agency). Normative Resolution #345/2008, issued on 16 December 2008 and subsequent amendments. ANEEL (Brazilian Electricity Regulatory Agency). Normative Resolution #414/2010, issued on 9 September 2010. Denis Bouyssou, Thierry Marchant, Marc Pirlot, Alexis Tsoukiàs, Philippe Vincke. “The lexicographic method,” in Evaluation and decision models with multiple criteria: Stepping stones for the analyst, v. 86. [S.I.]: Springer Science & Business Media, 2006, pp. 188-190.

22


Hydrodynamic Conditions and Photodegradation of Methyl Orange in a Fluidized Bed Photoreactor Reliance J. Mhlanga1, Nhlanhla Nyembe2, Haleden Chiririwa3 and Ochieng Aoyi4 1

Department of Chemical Engineering, Vaal University of Technology, Vanderbijlpark, 1900, RSA (phone: +27169509059; email: [email protected]) 2,3,4 Centre for Renewable Energy and Water, Vaal University of Technology, Vanderbijlpark, 1900, RSA (e-mail: [email protected], [email protected], [email protected])

Abstract: Advanced oxidation processes (AOPs) have emerged as promising techniques for the treatment of wastewater containing complex organic compounds. In this study, experiments were carried out to determine the effect of superficial gas velocity on the hydrodynamic conditions (average gas hold-up & bubble size) and the effect of operating conditions on the photodegradation of methyl orange (MO) in a fluidized bed photoreactor. Optimum operating parameters were found to be: time of 120 min, catalyst loading of 1.5 g/L and the superficial gas velocity being 212.23 mm/s. An increase in the superficial gas velocity increases the average gas hold-up and bubble size. The effect of hydrodynamic conditions on photodegradation showed that an increase in the superficial gas velocity results in an increase in the removal of color and total organic carbon (TOC) removal.

Keywords: Hydrodynamics, Methyl orange, Photodegradation, Photoreactor

1. Introduction In recent times, one of the major global problems is the access to clean water and only a few people in the world have access to clean water and sanitation. Freshwater is a fundamental resource for human well-being and the natural environment; it is regarded as the most essential natural resource in the world [1]. Over the past few decades, climate change and human socioeconomic development have greatly changed the global hydrological cycles, threatening human water security, the health of aquatic environments and river biodiversity [2]–[4]. The discharge of textile effluents to the water bodies has raised much concern because of potential health hazards associated with the entry of toxic components into the food chains of humans and animals [5]. The need to purify water previously considered clean has attracted a lot of interest from a lot of researchers recently, with various techniques having come into view [6]. Methyl orange (MO) is an azo dye that has been widely used in textiles, foodstuffs, paper and the leather industries [7]–[9]. However, the release of MO and its products into the environment causes serious pollution problems [10]. The effluent streams coming from textile plants must be treated in order to remove the toxic or carcinogenic dye residues and their by-products, whereas an effective effluent decolorization is usually required by most government regulations. Various methods of water treatment exist for treating industrial water contaminated with MO [11]. The photocatalytic treatment of wastewater containing dyes has also been widely reported as an alternative method of wastewater treatment [12]–[13]. The presence of MO in the environment causes pollution and threatens the aquatic species. There are various technologies available for the removal of MO from water. Most of these technologies are energy intensive and introduce chemicals which are not wanted in the first place. They also concentrate the pollutants into solid or liquid side streams which require additional treatment or disposal thus escalating the cost of effluent treatment [5]. As a result, the application of the heterogeneous photocatalytic oxidation (HPO) process as an advance 23

oxidation process (AOP) to degrade toxic organic pollutants has emerged as a robust and cost effective treatment method. The attractiveness of the HPO process to many researchers is due to its flexibility to employ ultraviolet (UV) light or solar and titanium dioxide (TiO2) to completely degrade toxic organic pollutants into biodegradable and less harmful products. In this work, the photocatalytic degradation of MO contaminated water was investigated using solar as a UV source and TiO2 as a photocatalyst. The aim of the study was to investigate the hydrodynamic conditions and optimize the operating conditions that affect the photodegradation of MO in a fluidized bed photoreactor. The main drawbacks in the commercialization of the HPO process are the cost of: UV light lamps and the separation of the catalyst post-treatment. These challenges were addressed, in the current study, by using sunlight as a UV source and by attaching the catalyst onto colloidal silica so as to form denser particle sizes. The act of forming denser particle sizes facilitates the post separation process. The use of solar energy may prove to be economically and technologically feasible, for water treatment and detoxification of wastewater [14]–[15].

2. Methodology 2.1.

Materials

Methyl orange was used as a model pollutant due to the fact that it is the most commonly present pollutant in textile wastewater. Hydrochloric acid [32% (v/v)] and sodium hydroxide (NaOH) were used to adjust the initial pH level of the solution and were obtained from Sigma Aldrich (South Africa). Commercial grade TiO 2 Degussa P25 was used as a photocatalyst, with surface area of 60-80 m2/g, particle size of 30 nm and was obtained from Merck (South Africa). A compressor was used to supply air for agitation. The pH level was measured using an Orion Star A111 pH meter (Thermo Scientific). The concentration of methyl orange was determined using the UV-vis spectrophotometer. The total organic carbon (TOC) in solution was determined by using the Teledyne Tekmar TOC Torch analyser. Solution turbidity was measured using a Hach DR2000 photometer using the FAU turbidity function.

2.2.

Solution Preparation

A stock solution of known concentration was prepared by dissolving the appropriate amount of MO powder in a determined amount of de-ionized water.

2.3.

Catalyst Preparation

The composite catalyst was prepared by binding TiO2 using silica xerogel. A Suitable quantity of TiO2 and colloidal silica were magnetically stirred until the mixture was homogeneous. The mixture was then laid on glass plates and dried at 60°C to remove the moisture. The dry sample was then sieved to a particle size range of 38 to 75 μm. The screened powder was then washed using 0.1 M HCl to remove the excess alkalinity and the excess acidity was neutralized by washing the catalyst particles several times with de-ionized water. Between each wash, the pH of the wash was monitored and the washing stopped when the pH value remained constant at about 6.5. The final composite catalyst product was obtained after drying at 60 oC.

2.4.

Experimental Setup

The experimental setup consisted of a fluidized bed photoreactor as shown in Fig. 1

24

(8)

(7)

(6)

(5)

(4) (2) (3) (1)

Fig. 1 Experimental setup. (1) Compressor; (2) Flowmeter; (3) Non-return valve; (4) Gas distributor; (5) Air bubbles; (6) Catalyst particles; (7) Fluidized bed photoreactor and (8) Degassing zone.

2.5.

Experimental Design

According to literature, the photocatalytic degradation of organic pollutants is significantly affected by these operating parameters: reaction time, catalyst loading [18], and superficial gas velocity [16] and these are shown in Table I. The method used to conduct the experiments is called the one-factor-at-a-time approach, where others variables are kept constant to determine the optimum level for each variable studied. TABLE I One factor at a time experimental Parameter

Levels

Reaction time (min) Catalyst loading (g/L) Superficial gas velocity (mm/s)

60 0.5 70.74

90 1* 141.49*

120* 1.5 212.23

*Parameters that were kept constant.

2.6.

Photodegradation Experiments

The photocatalytic activity of the prepared composite catalyst was tested for the degradation of MO with an initial concentration of 13 ppm. The photodegradation reaction was carried out in a fluidized bed photoreactor with a volume of 400 mL in the presence of air bubbling system. The following variables were studied: catalyst loading, superficial gas velocity and reaction time (Table I). Sampling was done at the beginning and end of each experiment. Before analysis, the samples at the end of each experiment were filtered through a 0.45 µm membrane syringe filter [17]. The amount of MO was quantified using a UV-Vis spectrophotometer at a wavelength of 464 nm.

2.7.

Hydrodynamics Experiments

The hydrodynamic experiments were carried out to determine the effect of superficial gas velocity on the average gas hold-up and bubble size. The photoreactor consisted of a sintered-plate type bubble distributor with a pore size of 10-15 µm. The bubble size and average gas hold-up measurements were carried out to characterize the fluidization behavior of the photoreactor. The average gas hold-up (εG) measurement was carried out by using the quick stop method [16] and was calculated by using (1): G 

HD  H H

(1)

where H is the liquid height with no gas sparging and HD is the displaced height during gas sparging.

3. Results And Discussion 3.1. Hydrodynamics The hydrodynamic conditions such as the average gas hold-up and bubble size in the fluidized bed photocatalytic reactor had a great influence in the photodegradation of MO. The gas hold-up plays a huge role in the rate of gas-liquid mass transfer which controls the amount of oxygen dissolved in 25

solution. The oxygen behaves like an electron scavenger which prevents electron-hole recombination during photocatalysis. This suggests that high oxygen mass transfer results in efficient photodegradation rates. The hydrodynamic experiments were carried out to determine the average gas hold-up and the bubble size distribution at different superficial gas velocities. The bubble size also has an effect on the rate of mixing in the system. 1) Effect of Superficial Gas Velocity on the Average Gas Hold-up The effect of superficial gas velocity on the average gas hold-up was investigated and the results are shown in Fig. 2. The results showed that an increase in the superficial gas velocity results in an increase in the average gas hold-up. This was caused by the decrease in the buoyant force experienced by the bubbles, thereby reducing the bubble slip velocity [20]. The average gas hold-up increased from 0.02 to 0.15 when the superficial gas velocity was increased from 70.74 to 282.97 mm/s. This was due to the fact that increasing superficial gas velocity increased the number of bubbles present in solution which resulted in an increase in the average gas hold-up. The same trend was also seen in the bubble size results (Fig. 4). Reference [19] obtained a similar trend when they studied the effect of superficial gas velocity on the overall gas hold-up.

Fig. 2 Average gas hold-up against superficial air velocity

2) Effect of Superficial Gas Velocity on the Bubble Size The effect of superficial gas velocity on bubble size was determined by varying the superficial gas velocity (70.74 to 282.97 mm/s). The results showed an increase in the bubble size with an increase in the superficial gas velocity. There are two operating regimes namely: homogeneous bubble flow regime where the bubble size ranges from 1-7 mm and the heterogeneous bubble flow regime which ranges from 20-70 mm. Fig. 3a to 3c shows that a homogeneous bubble flow regime exists and Fig. 3d shows a transitional bubble flow regime. When increasing the superficial gas velocity, the static liquid column expands and the volume fraction of bubbles increases with superficial gas velocity. Increasing the superficial gas velocity further results in a decrease in the photon efficiency in spite of the vigorous mixing of bubbles. Also the larger number of bubbles may hinder absorbance of solar light to the photocatalyst. Therefore, it is necessary to operate at an optimum superficial gas velocity that provides adequate mixing with minimal photon deficiency.

Fig. 3 Bubble size distribution.

26

Fig. 4 Bubble size against superficial gas velocity

3.2.

Photodegradation

1) Effect of Irradiation Time on the Removal of Color and TOC Fig. 5 shows the effect of reaction time on the removal of color and TOC. It can be seen that as the reaction time increases the solution becomes decolorized (reduction of color). Since the presence of color is directly proportional to the presence of MO, due to the fact that it is the pollutant that causes color. Therefore, the decolorization of the solution simply implies that there is removal of MO. The same decrease was seen on the TOC reduction results, the only difference is that TOC represents the degradation of the various organic compounds present in the solution. The results show that 80% of color was removed in 60 min, whereas, only 33.97% of TOC was removed at the same time. This suggests that most of the MO was degraded in 60 min, although, other MO derivatives are still present in solution as shown by the TOC reduction results. Reference [7] studied the photocatalytic degradation of MO in water using Ag/ZnO as a catalyst. They reported that irradiation of MO after 10 min produces other forms of methyl groups such as monohydroxlated products. Consequently, monitoring the reduction of TOC gives a clear indication on the degradation of MO and its derivatives.

Fig. 5 Effect of reaction time on the removal of color and TOC

2) Effect of Catalyst Loading on the Removal of Color and TOC The removal of color and TOC increased with an increase in the amount of catalyst as shown in Fig. 6. An increase in the catalyst loading results in an increase in the amount of catalyst particles present in the photoreactor. This, however, increases the amount of active sites available for MO adsorption and photodegradation [14]. Considering the range (0.5–1.5 g/L) of catalyst loading that was used in this study, 1.5 g/L was found to be the optimum loading since it achieved the highest color removal (~98 %) and TOC reduction (~79 %). Extrapolation of the data shows that increasing the catalyst loading beyond 1.5 g/L will cause a decrease in the removal of TOC and color. According to literature, this is referred to as the liming factor. This means that increasing the catalyst loading beyond the limiting factor will cause obstruction to the energy photons (UV light) from reaching the surface of the catalyst particles due to an excessive amount of catalyst particles present in the photoreactor [14]. Reference [18] obtained an optimum catalyst concentration of 100 mg/L (limiting factor) and showed that an increase in catalyst loading beyond this value results in the decrease in the total chemical oxygen demand (TCOD). It is therefore, recommended to operate at the limiting factor which gives maximum photodegradation and reduces the cost of catalyst loading. 27

Fig. 6 Effect of catalyst loading on the removal of color and TOC

3) Effect of Superficial Gas Velocity on the Removal of Color and TOC The introduction of air in a fluidized bed photoreactor is essential due to the fact that air plays two major roles in the photodegradation of pollutants. Air is used for mixing inside the reactor (hydrodynamics) and the oxygen is used to prevent electron-hole recombination. Therefore, Fig. 7 showed that, as the superficial gas velocity is increased, the removal rate of color and TOC increases. This indicates that an increase in the superficial gas velocity results in an increase in the number of bubbles, thus mixing between the TiO 2 catalyst and methyl orange is enhanced and a higher mass transfer rate is obtained. At higher superficial gas velocities, the bubble size increases (Fig. 4) which leads to a vigorous mixing inside the photoreactor. The optimum superficial gas velocity was found to be 212.23 mm/s. The hydrodynamic study revealed that at this superficial gas velocity (212.23 mm/s), the transitional bubble flow regime exists. It is evident from Fig. 7 that the hydrodynamics play a significant role in the photodegradation of MO.

Fig. 7 Effect of air velocity on the removal of color and TOC

4. Conclusion The purpose of this study was to investigate the hydrodynamic conditions and to obtain optimum conditions for methyl orange photodegradation in a fluidized bed photoreactor. It was shown that the photodegradation efficiency is significantly influenced by the hydrodynamics (superficial gas velocity), catalyst loading and reaction time. It was also shown that the superficial gas velocity affects the bubble size and average gas hold-up. The average gas hold-up increased from 0.02 to 0.15 when the superficial gas velocity was increased from 70.74 to 282.96 mm/s. The effect of hydrodynamic conditions on photodegradation showed that an increase in the superficial gas velocity results in an increase in decolorization and the removal of TOC. The optimum photocatalytic operating conditions were found to be: superficial gas velocity of 212.23 mm/s, catalyst loading of 1.5 g/L and reaction time of 60 min. It was evident that solar, as a renewable energy source, can be effectively applied in the photodegradation of MO. This study has revealed that the heterogeneous photocatalytic oxidation process can be effectively applied for the degradation of MO in wastewater. Although it was shown that the hydrodynamics significantly affect the photodegradation efficiency, a more in-depth study on the hydrodynamics is necessary for more transparency. Further work can be done to use computational or numerical

28

techniques to study hydrodynamic phenomena, light distribution in the reactor and photodegradation reaction kinetics.

5. Acknowledgment The authors would like to acknowledge the Water Research Commission (WRC) of South Africa for funding this project.

6. References [1] P. H. Gleick, “Water and conflict: Fresh water resources and International security,” International Security, vol. 18, 1993, pp. 79–112. [2] C. J. Vörösmarty, P. B. McIntyre, M. O. Gessner, D. Dudgeon, A. Prusevich, P. Green, S. Glidden, S. E. Bunn, C. A. Sullivan, C. R. Liermann, and P. M. Davies, “Global threats to human water security and river biodiversity,” Nature, vol. 467, 201, pp. 555–561. [3] D. Jacobsen, A. Milner, L. Brown and O. Dangles, “Biodiversity under threat inglacier-fed river systems,” Natural Climate Change, 2012, pp. 361–364. [4] M. T. H. Van Vliet, W. H. P. Franssen, J. R. Yearsley, F. Ludwig, I. Haddeland, D. P. Letten-maier, and P. Kabat, “Global river discharge and water temperature change,” Global Environment Change, vol. 23, 2013, pp. 450–464. [5] C. Hu, Y. Z. Wang, and H. X. Tang, “Destruction of phenol aqueous solution by photocatalysis or direct photolysis,” Chemosphere, 2000, pp. 1205–1209. [6] M. T. Amin, A. A. Alazba and U. Manzoor, “A Review of Removal of Pollutants from Water/Wastewater Using Different Types of Nanomaterials,” Advances in Materials Science and Engineering, 2014, pp. 1–24. [7] T. Chen, Y. Zheng, J. M. Lin and G. Chen G, “Study on the Photocatalytic Degradation of Methyl Orange in Water Using Ag/ZnO as Catalyst by Liquid Chromatography Electrospray Ionization Ion-Trap Mass Spectrometry,” Journal of the American Society for Mass Spectrometry, vol. 19, no. 7, 2008, pp. 997–1003. [8] P. M. K. Reddy, S. K. Mahammadunnisa and C. H Subrahmanyam, “Mineralisation of aqueous organic pollutants using a catalytic plasma reactor,” Indian Journal of Chemistry, vol. 53A, 2014, pp. 499–503. [9] C. Fleischmann, M. Lievenbrück and H. Ritter, “A Review: Polymers and Dyes: Developments and Applications,” Polymers, vol. 7, 2015, pp. 717–746. [10] S. Adhikari, D. Sarkar, “Preparation of Mixed Semiconductors for Methyl Orange Degradation,” Journal of Nanomaterials, 2015, pp. 1–8. [11] M. N. Rashed, “Adsorption Technique for the Removal of Organic Pollutants from Water and Wastewater,” Environmental Sciences, 2013, pp. 167–194. [12] V. Karthik, K. Saravanan, P. Bharathi, V Dharanya and C. Meiaraj, “An overview of treatments for the removal of textile dyes,” Journal of Chemical and Pharmaceutical Sciences, vol. 7, no. 4, 2014, pp. 301–307. [13] A. O. Ibhadon, P. Fitzpatrick, “A review: Heterogeneous Photocatalysis: Recent Advances and Applications,” Catalysts, vol. 3, 2013, pp. 189–218. [14] M. Khune, J. Akach and A. Ochieng, “Solar Photodegradation of Phenol using a Composite Catalyst of Silica and TiO2,” International Conference on Chemical Engineering and Advanced Computational Technologies, vol. 24-25, 2014, pp. 2–5. [15] S. Apollo, S. Maurice, M. S. Onyango and A. Ochieng, “Integrated UV photodegradation and anaerobic digestion of textile dye for efficienct biogas production using zeolite,” Chemical Engineering Journal, vol. 245, 2014, pp. 241–247. [16] M. Abraham, A. S. Khare, S. B. Sawant and J. B. Joshi, “Critical gas velocity for suspension of solid particles in threephase bubble columns,” Industrial Engineering and Chemistry Research, vol. 31, 1992, pp. 1136–1147. [17] S. Malato, P. FernańdezIbań˜ez, M. I. Maldonado, J. Blanco and W. Gernjak, “Decontamination and disinfection of water by solar photocatalysis. Recent overview and trends,” Catalysis Today, vol. 147, 2009, pp. 1–59. [18] F. Shahrezaei, Y. Mansouri, A. A. L. Zinatizadeh and A. Akhbari, “Process modeling and kinetic evaluation of petroleum refinery wastewater treatment in a photocatalytic reactor using TiO 2 nanoparticles,” Powder Technology, vol. 221, 2012, pp. 203–212. [19] M. Pourtousi, P. Ganesan and J. N. Sahu, “Effect of bubble diameter size on the prediction of flow pattern in EulerEuler simulation of homogeneous bubble column regime.” Measurement: Journal of the International Measurement Confederation, vol. 76, 2015, pp. 255–270. [20] P. Rollbusch, M. Beker, M. Ludwig, A. Bieberle, M. Grünewald, U. Hampel and R. Franke, “Experimental investigation of the influence of column scale, gas density and liquid properties on the gas holdup in bubble columns,” Internal Journal of Multiphase Flow, vol. 75, 2015, pp. 88-106.

29


Photocatalytic Degradation of Salicylic Acid and Reduction of Cr(VI) using TiO2 Ramataobane K. Mphela, William Msimanga, Kwena Y. Pete, Haleden Chiririwa and Aoyi Ochieng Vaal University of Technology, RSA: e-mail: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]

Abstract: Water pollution caused by organic and inorganic contaminants represents an important ecological and health hazard. In this study the photocatalytic reduction of Cr(VI) and degradation of salicylic acid (SA) in aqueous suspensions using commercial TiO2 was investigated. The effect of operating parameters such as photocatalyst loading, initial pollutant concentration and pH were optimized in aqueous solution containing salicylic acid alone and hexavalent chromium alone. The performance of the photocatalyst reactor was evaluated on the basis of salicylic acid removal and metal ion reduction. The rate of salicylic degradation for the ternary salicylic acid /Cr(VI)/TiO2 system were generally lower than that for the respective binary salicylic acid/TiO 2 systems. This could be attributed to partial catalyst deactivation to some extent.

Keywords: Chromium, photocatalysis, photocatalyst, salicylic acid.

1. Introduction The rapid development of civilization and industrial activities has led to a series of environmental problems. For many years, large amount of pollutants have been discharged into the environment intentionally or accidentally, including toxic metals in water with a great health concern [1]. Various organic and inorganic wastewaters have been produced and discharged from metal plating, mining, smelting, battery manufacture, tanneries, petroleum refining, paint manufacture, pesticides, pigment manufacture, printing and photographic industries [2]-[3]. Among the different industrial wastewaters, tannery effluents co-contaminated with organic and inorganic compound generated in the dyestuffs, textile, and leather cause serious effects to human health and aquatic life. Treatment of such pollutants from contaminated water is a complex challenge throughout the world, as the two components need to be treated independently using an effective and robust technique [4]. Different from the organic components such as salicylic acid, toxic metallic ions generally are not degradable and have an infinite lifetime, thus they may accumulate in living tissues, causing various serious diseases and environmental problems [5]. Some of the metal ions are actually necessary for human body in trace amounts while others are carcinogenic or toxic, damaging the nervous system, kidney, liver, skin, bones, or teeth [3]. The removal of toxic metals in an effective and economic way has been a critical issue for the environment improvement [6]. Among the heavy metal ions, Cr(VI) is one of the toxic, carcinogenic and mobile contaminant originating from various industrial processes such as pigment production, and leather tanning. In aquatic environments, chromium exists mostly in the hexavalent chromium Cr(VI) and trivalent chromium Cr(III) states. Anionic Cr(VI) is far more mobile and toxic than Cr(III) and more difficult to remove from water [7]-[8]. Similar to many other metal cations, however, aqueous Cr(III) can be readily precipitated as Cr(OH)3 or removed by adsorption and ion exchange. Thus, reduction of chromium from its hexavalent to trivalent states simplifies its removal from effluent and also reduces its toxicity and mobility [9-10]. Photocatalytic technology has been studied since 1970s and widely explored for the degradation of organic

30

and inorganic contaminants in the presence of certain semiconductors as catalyst under light exposure [3]-[11]. This technology is based on the photo-induced highly reactive electron/hole (e−–h+) pairs on TiO2 under illumination by light of energy greater than its bandgap. Holes and various oxygen containing radical species (•OH, O2−•, HO2•) play an important role in the photocatalytic oxidation of organic pollutants, while photogenerated electrons are critical to the photocatalytic reduction of heavy metal ions [12]. Whenever various catalysts (oxides, sulphides, etc.) have been tested under comparable conditions for degradation of the same compound, TiO2 has proved to have the highest photocatalytic activity with a large resistance to photo-corrosion. Titania has universally been recognized as one of the better photocatalysts in heterogeneous photocatalysis applications as it combines two important complementary features for a photocatalyst: good UV absorption efficiency for the light harvesting process and good absorption capacities, due particularly to the density of OH groups of amphoteric character [13]. Schrank et al. [14] investigated the UVA/TiO2 treatment of model solutions containing the dye luranzol S kong alone, Cr(VI) alone, as well as their mixture as a function of the substrate concentration and solution pH and reported that the rates of both dye oxidative degradation and Cr(VI) reduction in their mixture were faster than the respective rates in the single substrate systems. The aim of this study was to investigate simultaneous photocatalytic degradation of salicylic acid and reduction of chromium (VI) using titanium oxide. The effect of operating parameters such as initial pH, initial concentration and TiO2 catalyst dosage in the presence of UV irradiation for treatment of synthetic wastewater were investigated.

2. Experimental 2.1. Material TiO2 Degussa P25 was purchased from Merck Chemicals (Pty) Ltd., R.S.A. Salicylic acid (Aldrich +99%) was prepared by dissolving the solid in distilled water. All chemicals were of analytical reagent grade and used without further purification. Cr(VI) solution was prepared by dissolving an appropriate amount of K2Cr2O7 in distilled water. For simultaneous degradation runs, solution was prepared by mixing the corresponding volume of each starting solution of single substrates

2.2. Photocatalysis Experiments The photocatalytic experiments were carried out at room temperature (±25 ˚C) using a shaker. Experimental set up consists a UV lamp that was placed inside the reactor box ca 4 cm above the batch reactors inside the shaker. Aqueous solution volume of 100 ml containing either the salicylic alone, metal alone or their mixture was used throughout. . An 18W UV lamp with a maximum emission of 253.7 nm was used. The solution was left to equilibrate for 30 min in the dark before the lamp was switched on. In most cases, experiments were performed at an initial pH of 6.5. In those cases where runs were carried out at basic or acidic conditions, the initial pH was adjusted adding the appropriate amount of 1 M NaOH or H2SO4 as needed. Samples of about 5 mL periodically draw were centrifuged at a rotational speed of 14000 rpm to remove TiO 2 and then analyzed with respect to salicylic acid conversion, and Cr(VI) reduction.

2.3. Analytical methods The quantitative estimation of the salicylic acid was carried out using a UV–Visible spectrophotometer, model–118 at λmax of 300 nm. The Cr(VI) ion concentration was analysed by Atomic absorption spectroscopy (AAS).

3. Results and discussion 3.1. Effect of pH solution on single substrate: Cr(VI) or salicylic acid The reduction of Cr(VI) at different initial pH over time under different pH values is shown in Fig. 1. The Cr(VI) reduction gradually declined, with an increase in pH values. Higher reduction efficiency was obtained when experiments were performed in acidic solutions than that in alkaline solutions. At pH 2, the reduction rate was 75.3%, however, at pH 8, the reduction rate was approximately 49%. This can be explained by the negatively charged CrO42- that can associate with hydroxyl groups on composite photocatalyst surface via 31

electrostatic attraction with positively charged Ti-OH leading to a substantial reduction [15]. The decreased photoreduction of Cr(VI) at increased pH values is due to the electrostatic repulsion between negatively charged CrO42- and the negatively charged surface of the photocatalyst. 70

Reduction (%)

60 50 40

30 20 10

0 0

30

60

90 120 150 180 210 240 270 300

Contact time (min)

Fig.1. Effect of initial pH solution on photocatalytic reduction of Cr(VI): pH 2 (☐); pH 3 (Δ); pH 4 (◌); pH 5 ( ); pH 8 ( )

The effect of initial pH solution on the photodegradation of salicylic acid is shown in Fig. 2 where the behavior exhibited in Fig. 1 is also observed. Photodegradation was higher at acidic conditions than in basic conditions. At pH 2 degradation was about 85% and at pH 8 it was 60%. As seen from Fig. 2, degradation was strongly dependent on the solution pH and was substantially hindered at alkaline conditions. At pH 2 salicylic degradation was about 85 % and at pH 8 it was 60%. The effect of pH is more complicated. The isoelectric point for TiO2 was reported to be 6.5 [16]. The surface charge of TiO 2 becomes negative or positive depending if the pH is above or below the isoelectric point. Thus, in strong acidic and basic conditions TiO2 exists in the forms of TiOH2 + and TiO−, respectively. SA is a weak acid and acts in a similar manner existing as a positive or negative ion in strongly acidic or basic conditions. In consequence, the same polarity of charge on the surface and the SA molecule results in an electrostatic repulsion between them which possibly reduces the contacts of active radicals and model substance and thus lowers the degradation rate. In addition, decrease of OH radical production at strongly basic condition has been assumed which might also contribute to the degradation rate at pH 8 [17].The effect of pH has been contradictory in earlier studies. Hidaka et al. [16] found that the adsorption of SA on sol– gel coated TiO2 surface was the strongest in acidic pH, whereas the photocatalytic degradation was fastest in alkaline solutions (pH 9) where adsorption was the weakest.

Fig. 2 Effect of initial pH solution on photocatalytic degradation of salicylic acid: pH 2 (☐); pH 4 (Δ); pH 7 (◌); pH 8 ( ); pH 10 ( ) 32

3.2 Effect of catalyst concentration on single substrate: Cr(VI) or salicylic acid Figure 3 shows the photoreduction trends of Cr(VI) at different TiO2 concentration. It was observed that the photoreduction increased when the catalyst concentration was increased from 0.1 to 0.5 g/L. At 0.5 g/L the increased is not substantial showing that the catalyst has reached its maximum performance. Decreased photoreduction efficiency at higher catalyst dosage has been observed in photocatalytic reactions [18]. This behavior may be attributed to the shielding at higher concentrations where the TiO 2 photocatalyst reduces the penetration of light to the solution.

Reduction (% )

80

60

40

20

0 30

130 230 Contact time (min)

330

Fig. 3 Effect of initial TiO2 concentration on photocatalytic reduction of Cr(VI): 0.1 g/L (☐); 0.2 g/L (Δ); 0.3 g/L (◌); 0.4 g/L ( ); 0.5 g/L ( )

In general, any catalyst will suffer from deactivation to an extent during its service. It is observed in Fig. 4 that initially the degradation of salicylic reduced with an increase in photocatalyst concentration. This was more pronounced at 0.5 g/L photocatalyst concentration which can be due to the partial deactivation of activated molecules by collision with ground state molecules. When the photocatalyst concentration exceeded 0.4 g/L, the degradation efficiency decreased thus causing light scattering and a screening effect while reducing the photocatalytic activity of the composite photocatalyst. The results suggested that an optimal concentration of the photocatalyst is necessary for efficient degradation.

Removal (% )

100

80

60

40

20

0 0

30 60 90 120 150 180 210 240 270 300

Contact time(min)

Fig. 4 Effect of initial concentration TiO2 on the photocatalytic degradation salicylic acid: 0.1 g/L (☐); 0.2 g/L (Δ); 0.3 g/L (◌); 0.4 g/L ( ); 0.5 g/L ( )

3.3. Effect of initial solution concentration on single substrate: Cr(VI) or salicylic acid The effect of initial Cr(VI) concentration on Cr(VI) photoreduction was investigated over the range of 2 to 10

33

mg/L (Fig. 5). Cr(VI) reduction efficiency gradually decreases with an increase in initial concentration of Cr(VI). After 200 min, the reduction of Cr(VI) was 76.7% at initial metal concentration of 2 mg/L and 32.5% at concentration of 10 mg/L under the same operating conditions. The slow photocatalytic reduction of Cr(VI) in the absence of organic compounds is not due to the deactivation of the photocatalyst, however, due the net photocatalytic reaction in a completely inorganic aqueous solution is the three electron reduction of Cr(VI) to Cr(III) with oxidation of water to oxygen, which is a kinetically slow four-electron process [19]. 80

Reduction (% )

60

40

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0 0

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100 150 contact time (min)

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Fig. 5 Effect of initial concentration on the photocatalytic reduction of Cr(VI): 2 mg/L (☐); 4 mg/L (Δ); 6 mg/L (◌); 8 mg/L ( ); 10 mg/L ( )

In Fig. 6, it can be seen that as the initial concentration increased, the degradation decreased. This result can be described by considering the competition for absorption of the limited quantity of available photons by the salicylic acid. The salicylic acid degradation as function of concentration was faster with an initial concentration of 50 mg/L compared to 10 mg/L. These results might be described by the fact that at higher concentrations more SA molecules are in the vicinity of the catalytic surface and ready to react with constantly emerging shortlived hydroxyl radicals. These results are consistent with the study conducted by Vilhunen et al. [20] where the salicylic acid degradation as function of concentration was determined with catalyst sample TiO2 T300 and it was found faster with an initial concentration of 75 mg/L compared to 10 mg/L. 100

Removal (%)

80

60

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0

30

60

90

120

150

180

210

240

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Fig. 6 Effect of initial concentration on the photocatalytic degradation of salicylic acid 10 mg/L ( ); 20 mg/L ( ); 30 mg/L (◌); 40 mg/L (Δ); 50 mg/L (☐);

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3.4. Photocatalytic reaction with multiple substrate: Cr(VI) and salicylic acid The wastewater contaminated by toxic heavy metals often co-exists with organic pollutants in actual wastewater pollution systems. Theoretically, the photocatalytic reduction of Cr(VI) on TiO2 should be more efficient in the metal-organic-TiO2 system than in the single system due to the accelerating effect by the preferential photocatalytic oxidation of the organics. In such metal-organic-TiO2 system, the organic compound receives holes from valence band directly or indirectly, and is oxidized [21]. Thus increasing the photoreduction efficiency of Cr(VI) by suppressing the electron-hole recombination. In an attempt to understand how salicylic acid influences Cr(VI) reduction under photocatalytic conditions, Cr(VI) reduction was analyzed on the systems containing different initial Cr(VI) acid concentration. A higher reduction of Cr(IV) was observed in a binary system than is a single system (Fig. 6 and 7).

Fig. 7 Effect of Cr(VI) initial concentration on salicylic degradation (black bars) over TiO2 and final Cr(VI) reduction (hatched bars). Condition: Co= 50 mg/L; pH= 2

4. Conclusion The aim of this study was to investigate the heterogeneous photocatalytic degradation of salicylic acid and reduction of Cr(VI). It was observed that variation of the TiO2 photocatalyst concentration plays an important role in degrading pollutants. The present study indicated that the photocatalytic degradation efficiency initially increases with photocatalyst concentration and then decreased at high values due to light scattering and screening effects. The most interesting result of the study was that the highest degradation of SA with TiO 2 was achieved at higher initial concentration. The presence of salicylic acid significantly improved the photoreduction of Cr(VI) ion into non-toxic Cr (III) ion.

5. Acknowledgements The financial support of the Water Research Commission, South Africa is sincerely acknowledged.

6. References [1] H Shayler and M McBride “E Harrison, Sources and Impacts of Contaminants in Soils, Cornell Waste Management Institute” Cornell Waste Management Institute, 2009, pp. 1-6. [2] W. S Wan Ngah and M. A. K Hanafiah, “Removal of heavy metal ions from wastewater by chemically modified plant wastes as adsorbents”: A review. Bioresource Technology, 2008, 99(10) pp. 3935-3948. [3]

H Zhou “Photocatalytic reduction of hexavalent chromium in aqueous solutions by TiO 2/PAN nanofibers” MSc Thesis, Dept. Chemical. Eng., University of Missouri-Columbia, 2013

[4]

K.Y Pete, M.S Onyango, M Sillanpää, A. Ochieng “Kinetic Modeling of the Photocatalytic Reduction of Cr(VI) in the Presence of Dye Using Composite Photocatalyst” Journal of Chemistry and Chemical Engineering, 2014 (8) 918924 35

[5] S. J Khan “Quantitative chemical exposure assessment for water recycling schemes” Waterlines Report Series No 27, Australian Government National Water Commission, 2010, pp.1-207. [6] M. T Amin, A. A Alazba and U Manzoor “A Review of Removal of Pollutants from Water/Wastewater Using Different Types of Nanomaterials” Advances in Materials Science and Engineering, 2014, pp. 1-24. [7] S Focardi, M Pepi and S. E Focardi “Microbial Reduction of Hexavalent Chromium as a Mechanism of Detoxification and Possible Bioremediation Applications” Biodegradation-Life Science, 2013, pp. 321-347. [8]

C Rosales-Landeros, C. E Barrera-Díaz1, B Bilyeu, V. V Guerrero and F. U Núñez “A Review on Cr(VI) Adsorption Using Inorganic Materials” American Journal of Analytical Chemistry, 2013, 4, 8-16.

[9] C Lao-Luque, M Solé, X Gamisans, C Valderrama and A. D Dorado “Characterization of chromium (III) removal from aqueous solutions by an immature coal (leonardite). Toward a better understanding of the phenomena involved” Clean Technologies and Environmental Policy, 2014, Vol.16, 1, pp. 127-136. [10] A. M Al-Haj-Ali and L. M Marashdeh, Removal of Aqueous Chromium (III) Ions Using Jordanian Natural Zeolite Tuff in Batch and Fixed Bed Modes, Jordan Journal of Earth and Environmental Sciences, 2014, Vol 6, 2, pp. 45-51. [11] M Umar, and H.A Aziz, “Photocatalytic Degradation of Organic Pollutants in Water, Organic Pollutants - Monitoring, Risk and Treatment” 2013, pp. 195-208. [12] K Kabra, R Chaudhary and R. L Sawhney, “Treatment of Hazardous Organic and Inorganic Compounds through Aqueous-Phase Photocatalysis: A Review” Industrial & Engineering Chemistry Research, 2004, 43 (24), pp. 7683– 7696 [13] G Colón, M. C Hidalgo, J. A and Navío, “Influence of Carboxylic Acid on the Photocatalytic Reduction of Cr(VI) Using Commercial TiO2”, Langmuir, 2001, 17 (22) pp.7174–7177 [14] S.G Schrank, H.J José and R.F.P.M Moreira, “Simultaneous photocatalytic Cr(VI) reduction and dye oxidation in a TiO2 slurry reactor” Journal of Photochemistry and Photobiology. A: Chemistry. 2002, pp. 147:71-76. [15] S Asuha, X.G Zhou, and S Zhao, “Adsorption of methyl orange and Cr(VI) on mesoporous TiO2 prepared by hydrothermal method”, Journal of Hazardous Material, 2010. 181, pp. 204-210 [16] H Hidaka, H Honjo, S Horikoshi, and N Serpone, “Photocatalyzed degradation on TiO 2-coated quartz crystal microbalance. Adsorption/desorption processes in real time in the degradation of benzoic acid and salicylic acid”, Catalysis Communication, 2006, 7, pp. 331–335 [17] H.S Lee, T Hur, S Kim, J.H Kim, and H.I Lee, “Effects of pH and surface modification of TiO2 with SiOx on the photocatalytic degradation of a pyrimidine derivative”, Catalysis Today, 2003, 84, pp. 173–180 [18] R Asahi R, T Morikawa T, T Ohwaki, K Aoki , and Y Taga , “Visible-light photocatalysis in nitrogen-doped titanium oxide”s, 2001, Science, 13, 293, pp. 269-271. [19] G Colon, Hidalgo, M.C.and Navio, J.A. 2001. Photocatalytic deactivation of commercial TiO 2 samples during simultaneous photoreduction of Cr (VI) and photooxidation of salicylic acid”. Journal of Photochemistry and Photobiology A, 138(1): pp. 79-85. [20] S Vilhunen, M Bosund, M Kääriäinen, D Cameron, and M Sillanpää “Atomic layer deposited TiO 2 films in photodegradation of aqueous salicylic acid”, Separation and Purification Technology, 2009, 66 (1-66) pp. 130-134. [21] Z He, Q Cai, M Wu, Y Shi, H Fang, L Li, J Chen, and J, S, Chen “Photocatalytic Reduction of Cr(VI) in an Aqueous Suspension of Surface-Fluorinated Anatase TiO2 Nanosheets with Exposed {001} Facets”, Industrial & Engineering Chemistry Research, 2013, 52 (28), pp. 9556–9565

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Seamless Channel Spacing in Multiple Wavelength Fiber based Lasers M. Ajiya1*, J. A. Oladapo1, U. G. Danbatta2, N. A. M. Ahmad Hambali3 1

Department of Electrical Engineering, Faculty of Engineering, Bayero University, 3011, Kano, Nigeria 2 Nigerian Communications Comsission, Plot 423, Aguiyi Ironsi Street, Maitama, Abuja, Nigeria. 3 Semiconductor Photonics & Integrated Lightwave Systems (SPILS),Tun Abdul Razak Laser Laboratory (TAReL),School of Microelectronic Engineering,Universiti Malaysia Perlis,Pauh Putra Main Campus,02600, Arau, Perlis, Malaysia ⃰ Corresponding author: [email protected]

Abstract: The spacing between channels in multiple – wavelength Brillouin based fiber lasers are inherently 0.08 nm (10GHz). We demonstrate multiple – wavelength Brillouin/Erbium fiber laser in the Long wavelength band where the spacing between channels can seamlessly be achieved by changing the values of interferometer delay inserted within the laser cavity. The experimental setup is simulated in Optisystem environment. When the time delay of the interferometer was set at 0.1 ns, spacing between channels stood at the usual 0.08 nm. When the time delay was adjusted to 0.01 ns, the spacing between the generated channels stood at 0.8 nm. The demonstrated laser mitigates the problem associated with fixed channel spaced laser structures.

Keywords: Brillouin Fiber Laser, Delay, Interferometer, Stimulated Brillouin scattering, Wavelength Channel Spacing

1. Introduction Multi-wavelength fiber lasers have attracted remarkable research interest due to its wide applications in optical communications [1-4]. Notable architecture for the generation of multi-wavelength sources in fiber lasers is what has come to be known as Multi-wavelength Brillouin – Erbium Fiber laser (MWBEFL). MWBEFL was first reported by Cowle and Stepanov in 1996 [5]. It is obtained by in integration of linear gain obtained from Erbium doped fiber (EDF) and nonlinear Brillouin gain obtained from stimulated Brillouin scattering (SBS) effect in optical fiber. Since the introduction of MWBEFL, various types of laser cavity have been reported [68]. The spacing between channels in silica based optical MWBEFL is inherently 10 GHz (0.08 nm) because of the Doppler effects (change in frequency and wavelength of a wave for an observer moving relative to the source of the waves) [9]. However practical contribution of MBEFL in a practical optical communication system implementation is limited due to the difficulty of channel multiplexing from the narrow (10 GHz) spacing. Therefore attempts have been made to increase the spacing between channels so that multiplexing and demultiplexing can be achieved with ease in MBEFL. Several works have been reported where double Brillouin frequency (20 GHz or 0.16 nm) has been achieved in MWBEFL [10-12]. 37

In this paper, we demonstrate an MWBEFL in the L – band region that utilizes delay interferometer filter in its lasing cavity. By simply changing the time of delay in the interferometer, we discovered that flexibility in channel spacing is obtained. When the time delay of the interferometer was set at 0.1 ns, spacing between channels stood at the usual 0.08 nm. When the time delay was adjusted to 0.01 ns, the spacing between the generated channels stood at 0.8 nm. The experimental setup is simulated in Optisystem environment, a comprehensive software design suite for photonics provided by Optiwave Systems Inc.

2. Simulation Set – Up The simulation set up of the L-Band Brillouin Erbium fiber laser utilizing Delay interferometer for channel spacing is depicted in Figure1. The set up consist of continuous wave laser at a wavelength of 1600 nm and power of – 47 dBm, Erbium doped fiber amplifier (EDFA) with a gain of 65dB, delay interferometer at wavelength of 1600 nm, optical circulator, loop control, ideal isolator, single mode fiber (SMF) of 25 km length, attenuation of 25dB, 16.75ps/nm/km of dispersion and optical spectrum analyzer (OSA) with resolution bandwidth of 0.01nm. The circuit is implemented in Optisystem, optical system simulation software. The continuous wave laser amplified by the EDFA is used as Brillouin pump (BP). In order to experience SBS effect, a higher BP power is required. The amplified signal is directed to the Delay Interferometer. The signal passes into the circulator and then, it is guided into the SMF. Then the cavity is formed. When the total gains in the cavity, (i.e. Brillouin gain and EDFA gain) are equal to the cavity loss, lasing action starts. The main purpose of EDFA gain is to compensate for the loss in the laser cavity so that SBS effect can be initiated and also to increase the laser output power. The lasing continues, provided the gain in the cavity is equal or greater than the cavity loss. The channel spacing between the Stokes and anti-Stokes is determined by the delay of the Interferometer. The laser’s output is measured by Optical Spectrum Analyzer (OSA) connected to the Isolator and Circulator. The output signal measured after isolator is referred to as transmitted signal while the output signal at port 3 of circulator is termed reflected signal.

Fig. 1MBEFL Assisted by Interferometer Delay

3. Results and Discussions Channel spacing as well as the number of output channels produced by L-Band MBEFL utilizing delay interferometer filter was first studied. The time of delay in the interferometer filter is varied from 0.01ns to 0.1ns. It should be noted that at double transmission trip (time delay) which is equivalent to two cascaded delay interferometer, the channel spacing between two adjacent lasing lines reduces. Therefore, multiple transmission trips (time delay) through delay interferometer will further reduce the wavelength spacing and increase the number of output channels [13]. The variation of time delay of interferometer filter with the Channel spacing produced (wavelength spacing between two adjacent lasing lines at different time delay of the interferometer) is given in Figure 2. At 0.025 ns delay, wavelength spacing between two adjacent transmission peaks is 0.33 nm

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while the adjacent wavelength spacing between two transmission peaks is 0.17 nm at 0.05 ns of time delay of interferometer filter. The reason being that the delay Interferometer acts as a comb filter which makes the wavelengths that match the peaks of the comb oscillates when it is in laser cavity. The wavelength spacing between two adjacent transmission peaks is 0.33nm (t=0.025ns) for one transmission trip.

Fig. 2: Wavelength channel spacing against Time delay of the Delay Interferometer.

For the double transmission trip which is equivalent to two cascaded delay interferometer, channel spacing between two lasing lines is reduced. Therefore multiple transmission trips through delay interferometer will further reduce the wavelength spacing and increase the number of output channels.

Fig. 3: Output Channels generated against wavelength channel spacing.

In Figure 3, total number of generated output channels against channel spacing is presented. It can be seen from Figure 3 that at channel spacing of 0.08 nm, total of 64 output channels comprising of both Stokes and Anti-Stokes signals are generated while at 0.33 nm channel spacing only 16 output channels are produced.

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The output spectra of the MWBEFL at EDFA gain, Brillouin wavelength and Brillouin power of 65dB, 1600nm and -47dBm respectively with selected delay time in the range of 0.01nm to 0.1nm are shown in Figures 4a-d. These Figures clearly shows the wavelength channel spacing and the number of output channel generated from the demonstrated MWBEFL. It can be clearly seen from figure 4 that as the transmission trip (time delay) is increasing, the spacing between adjacent channels reduces but with increase in number of output channels and vice versa. At the maximum time delay of 0.1ns about 64 output channels with 0.08nm spacing between adjacent channels were obtained while the least time delay of 0.01ns produced only 6 output channels with 0.8 nm spacing between adjacent channels. Therefore, a trade – off exists.

Fig. 4(a)

Fig. 4(b)

Fig. 4(d)

Fig. 4(c)

Fig. 4: Output spectrum of wavelength Channel spacing and number of output channel generated at different Time Delay of Interferometer Filter.

4. Conclusion Multi-wavelength Brillouin Erbium fiber laser that utilizes delay interferometer as a comb filter has successfully been demonstrated. The laser system is simulated in the Optisystem environment. The influence of time delay and its effect on the generation of output channels in the demonstrated MBEFL was reported. When the demonstrated laser system was set at the standard spacing between channels of 0.08 nm, 64 output channels are generated. However, when the spacing between channels was set to 0.8 nm, only 6 output channels are 40

produced. The demonstrated laser provides a seamless spacing between lasing channels in fiber based lasers thereby providing solutions against channel multiplexing due to narrow spacing between lasing channels.

5. References [1] S. W. Harun, X. S. Cheng, P. Poopalan, and H. Ahmad, "Self-excited brillouin–erbium fiber laser for DWDM applications," Optics and Laser Technology, vol. 39, pp. 94-97, 2007. [2] Y.-J. Kim, B. J. Chun, Y. Kim, S. Hyun, and S.-W. Kim, "Generation of optical frequencies out of the frequency comb of a femtosecond laser for DWDM telecommunication," Laser Physics Letters, vol. 7, pp. 522 - 527, 2010. [3] L. Talaverano, S. Abad, S. Jarabo, and M. Pez-Amo, "Multiwavelength fiber laser sources with Bragg-grating sensor multiplexing capability," Journal of Lightwave Technology, vol. 19, p. 553, 2001. [4] R. Slavik and S. LaRochelle, "Multiwavelength single-mode erbium doped fiber laser for FFH-OCDMA testing," in Optical Fiber Communications Conference, Anaheim, California United States, 2002, pp. 245-246. [5] G. J. Cowle and D. Y. Stepanov, "Multiple wavelength generation with Brillouin/erbium fiber lasers," IEEE Photonics Technology Letters, vol. 8, pp. 1465-1467, 1996. [6] N. Ahmad Hambali, M. Ali Toor, Z. Yusoff, and M. Ajiya, "L-band multi-wavelength Brillouin/Raman fiber laser utilizing the reverse-S-shaped section," Journal of Nonlinear Optical Physics & Materials, vol. 23, pp. 1450026-10, 2014 2014. [7] M. N. Mohd Nasir, Z. Yusoff, M. H. Al-Mansoori, H. A. Abdul Rashid, and P. K. Choudhury, "Broadly tunable multiwavelength Brillouin-erbium fiber laser in a Fabry-Perot cavity," Laser Physics Letters, vol. 5, pp. 812 - 816, 2008. [8] M. N. M. Nasir, Z. Yusoff, M. H. Al-Mansoori, H. A. A. Rashid, and P. K. Choudhury, "Low threshold and efficient multi-wavelength Brillouin/erbium fiber laser incorporating a fiber Bragg grating filter with intra-cavity pre-amplified Brillouin pump," Laser Physics Letters, vol. 6, pp. 54 - 58, 2009. [9] G. S. He and S. H. Liu, Physics of Nonlinear Optics. Singapore: World Scientific, 1999. [10] S. W. Harun, M. R. Shirazi, and H. Ahmad, "A new configuration of multi-wavelength Brillouin fiber laser," Laser Physics Letters, vol. 5, 2008. [11] Y. Shee, M. Al-Mansoori, A. Ismail, S. Hitam, and M. Mahdi, "Multiwavelength Brillouin-erbium fiber laser with double-Brillouin-frequency spacing," Optics Express, vol. 19, pp. 1699-1706, 2010. [12] N. A. Hambali, M. Al-Mansoori, M. Ajiya, A. A. A. Bakar, S. Hitam, and M. Mahdi, "Multi-wavelength BrillouinRaman ring-cavity fiber laser with 22-GHz spacing," Laser Physics, vol. 21, pp. 1656-1660, 2011. [13] K. Suganya and D. S. Sundar, "Hybrid Gain Medium used in Multiwavelength Ring Laser for Noise Reduction," International Journal of Computer Applications, vol. 67, pp. 1 - 4, 2013.

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Planning Public Spaces through Urban Lighting Roghiyeh Samani Parsa University of Toronto

Abstract: Lighting design has given rise to urban context and public space in recent decades, and this stimulates our senses and perception that involves the fusion of art and architecture. Lighting design and the urban nightscape provides the urban space with safety. It gives cultural and economic vitality to urban centers and public spaces. Application of light in urban context creates more dynamic spaces and permits the emergence of public spaces that control the sensations of onlookers. In this paper I would like to study the lighting design in generating the impact in urban spaces, to find out the different aspects dealing with transformation of building and space into veritable mechanism of interaction with their context and the public.

Keywords: lighting, urban design, public space, nightscape

1. Introduction Lighting design in public spaces acts as an instrument of communication, totally connected with the senses. So the lightened public space is experienced through the perception of qualities of space, and the constant interaction of senses articulates the reality. This created reality is people’s new made reality at night life of cities that has different variables depending to lighting design and its different elements. Architectural lighting design focuses on aesthetic appeal. the lighting designer attempts to raise the general attractiveness of the design, measure whether it should be subtly blended into the background or whether it should stand out, and assess what kind of emotions the lighting should evoke [1]. Considering the different concepts that should be transferred to the people in different public spaces and different occasions through nightscape; lighting architecture including color, techniques, and elements should be studied.

2. The Non-Materialistic Concept Our perception of space has been focused on sight and touch, leaving other senses to other side. Buildings are created as images of instantaneous persuasion, as a photograph that produces a single description of an object [2]. However public space is of interdisciplinary nature and should be designed and perceived as a dynamic issue3. Lighting design could give this quality to public space. Since light is more than just a functional medium. Light is the most non-materialistic concept in the nature and when it combines with architecture, it has an expressive effect on people since all senses are involved.

3. Light In Design Process At nightfall the space is transformed and the appearance of forms and materials changes. Lighting design in public space links art, architecture, and technology together, since all of named elements work together and make a unit idea of lighting architecture installed and work in the urban space. This concept has recently been studied and applied in a different way compared to how it was used in the history of lighting. It was only at the end of twentieth century that architects began to treat artificial light as an integral element of the design process. Before that, light was just treated as a means of providing visibility, safety and security.

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Both night and day began to be considered in the design process, to give equal importance to a building’s night and day appearance [3]. Public space has both day and night life too. One in the day light, and the other at night which it is totally transformed, as the scale of the forms and spaces is altered at night. This is the magic, illusion, and design capability that light creates; making some surfaces, buildings, murals, sculptures, or facades colored and concentrated; while other surfaces are dark and visually deleted from people’s perception. Also it could give joyfulness to the space using special rhythm made by light. The methodology for lighting design for public space could be the appreciation for valuable characteristics of the context of each project. It could be cultural, historical, etc.

4. Spatial Functions The way people understand the environment, occurs through immediate sensory experience with memories from the past. Specific places and moments generate particular knowledge and understandings. This leads people to recognize particular things or respond in specific ways [4]. Lighting is an effective tool for designing the space, explaining the spatial function and movement, and accentuating and strengthening the spatial relations and tensions [5]. By combining light as the non-materialistic elements of space, and the concrete forms of architecture; design approaches from a single vision to the perception of the correlation between space, senses, and people.

5. Color One of the guiding elements of lighting design is color and the sensation produced by color depends upon its setting [6]. Color could emphasize on visibility, transparency, and forms. If the color of a well-known shape is changed, our perception of it also changes. Color also shapes the memory. It alters moods and has its own intrinsic properties in lighting; just like in any other way of application. It transforms the experience of objects and alters their state. For example in light installations, the statue in the middle of a square becomes just a screen for projecting different shapes with light [7]. So no one would see the statue, but the new built shapes used by lighting. The other example is when we use un-normal colors for specific objects, like projecting red color on trees.

6. Temporary Urban Lighting Illuminations events and temporary urban lighting happen in public spaces during special occasions’ in cities. One of those is the annual events of the New Year taking place at main squares and plazas [8]. Since the nature of temporary lighting design is based on an occasion of happiness in the large scale of the city population, providing the probative and joyful concept is the most important part in temporary lighting in public spaces. The other one is lighting festivals. Lighting festivals have an important role in the advancement of urban lighting design. Lighting designers, urban planners, civil engineering departments, public utilities, and civic leaders reexamine their own urban environments and ask how lighting affects the experience and perception of their cities. For lighting to become truly integrated into the fabric of the urban environment, all parties must work together and hold as a common goal the desire to create harmonious, environmentally, and contextually sensitive lighting [9].

7. Conclusion Few cities have incorporated aesthetic considerations for lighting into urban planning initiatives. As a result, the particular demands of individual projects have guided the design, type and quality of light – whether designed by architects, landscape architects, engineers or lighting designers. However unlike other urban features, lighting cannot be designed in isolation as its glow affects the greater urban environment. Architects and lighting designer should explore the relationship between space and light, and urban planners and cities planning departments should emphasize a greater relationship, that of city and light by coordinating the illumination of public spaces to reinforce a comprehensive and cohesive urban design.

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8. References [1] Miller. F. Kritine, Designs on the Public, University of Minnesota Press, Minneapolis, London, 2007. [2] Gaventa. Sarah, New Public Spaces. Mitchell Beazley, Octopus Publishing Group Ltd, Great Britain, 2006. [3] Gehl. Jan, Gemzoe. Lars, New City Spaces, The Danish Architectural Press, Copenhagen, 2000. [4] Bahamon. Alejandro, Alvarez. Maria, Light, Color, Sound. Parramon Ediciones, S. A., Barcelona, 2010. [5] Santen. Christa, Light Zone City: Light Planning in the Urban Context, Birkhauser Basel, 2006. [6] Stern, A. M. Robert, The Structure of Light: Richard Kellyand the Illumination of Modern Architecture, Yale University Press, 2015. [7] Isenstadt. Sandy, Mail Pretty. Margaret, Cities of Light: Two Centuries of Urban Illumination, Routledge, 2015. [8] Kaoru and Lighting Planners Associates, Lighting Design: For Urban Environments and Architecture, Azur Corporation, 2006. [9] Isenstadt. Sandy, Mail Pretty. Margaret, Cities of Light: Two Centuries of Urban Illumination, Routledge, 2015. oghiyeh Samani Parsa became a Member of ULI, Urban Land Institute Toronto, since 2015; she is a member of Iranian Construction Engineers Organization, and Illumination Engineering Society of Iranians. She is born in Tehran, Iran. She is a Master of Urban Design Candidate at University of Toronto, Canada, 2016 and has a Master’s Degree in Architecture from Iran University of Science and Technology, Tehran, Iran. She provided architectural design services for large-scale urban design projects in Tehran for over 10 years. She has presented papers in International Conferences in Europe and Canada, and wrote articles on subjects of architecture and lighting design; amongst them are Vancouver, Canada: Cultural Effects on Urban Design and Architecture, 2009, USA, Tucson: Place or Non-Place, 2015, and Iran, Tehran: Religious Symbols in Iran Architecture, 2001. She is interested in the concept of void and lighting in the urban fabric. Ms. Samani Parsa has received award for Architectural Lighting Design of Azadi Tower from Municipality of Tehran. She is now working on the idea of multi-layer pedestrian pathways, and improving the public activities in the urban spaces through the Public Spaces Project, Toronto, Canada.

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Simulation of Seismic Performance of Reinforced Concrete Verified with Experiment Melaku Sisay Abebe1, a, Hong sheng Qiu2,b 1 2

School of TransortationWuhan University of Technology, 430063, Wuhan Hubei, China School of Transortation, Wuhan University of Technology, 430063, Wuhan Hubei, China a [email protected], [email protected]

Abstract---The damage of reinforced concrete structure during earthquakes is a major engineering problem and so better understanding of causes which contribute to such damage is absolutely necessary. These structures are in need of an action whether to replace them or repair them, otherwise they will be the major cause of catastrophic collapse of civil infrastructure and consequent lives lose. This paper studied modeling of seismic performance of reinforced concrete and verified with laboratory experiment. LS_DYANA is a powerful finite element dynamic analysis soft wear which is commercially available in the market employed to model seismic performance of reinforced concrete. Besides laboratory experiment has been carried out to evaluate the seismic performance of half scale reinforced concrete. A comparison of load-deflection curves from tests and finite element analyses was carried out to validate the accuracy of the model. In general, the results show that the damage of reinforced column does capture the structural behavior of the columns satisfactorily. However, it was observed that the results from the finite element analysis gave a lower capacity after yield than that of the tests. Keywords----Damage index, LS_ DYANA, finite element, dynamic analysis, earthquakes.

1. Introduction Multiple earthquakes occur around the world where complex faults and cracks are observed to exist as physical failure. In most failure cases, the damage is mainly due to dramatic loss of material stiffness and strength of structural element as a result of materials deterioration under repeated earthquake dynamic load. The stiffness and the strength degradation significantly affect the dynamic characteristics of damaged structures and hence their response under subsequent earthquakes [1]. Reinforced concrete has been a widely used as construction material in protective structures for long time[2]. There are several alternatives in material and framing of building structures designed for gravity, wind or seismic loads. However reinforced concrete material has been primarily used for floor and wall construction of protective structures due to serviceability, ductility and strength performance of the material when subjected to extreme dynamic loads. Reinforced concrete structures are usually designed for linear-elastic response when subjects to sustained loads such as gravity and wind loads. Seismic loads subject structures are designed to a non-linear response [4]. It is important to characterize the non-linear response of reinforced concrete structural members and elements when subjected to extreme dynamic loads with a reasonable confidence. The damage of reinforced concrete structure during earthquakes is a major engineering problem and so better understanding of facts which contribute to such damage is absolutely important. The seismic design criteria of concrete structures is aiming to prevent structures damage and avoiding collapse or serious structural damage due to occurrence of infrequent earthquakes [5]. This concept means that some concrete structures might be damaged to some extent when they are subjected to severe earthquake excitations. It becomes very important to evaluate the degree of concrete structural damage so as to evaluate their post-earthquakes serviceability. Designing of structures to sustain earthquake demands within the elastic range is usually cost prohibitive. Thus, concrete structures should be provided with sufficient ductility and energy dissipation capacity such that they can undergo inelastic reversal displacements, meeting design requirements. Under severe earthquake 45

excitation, considerable structural damage without collapse may be allowed [6]. Furthermore, in a multi-level performance-based design or assessment procedure, concrete structures need to satisfy performance requirements under different levels of seismic demand. Therefore, there is a need to quantify damage under different levels of seismic ground motion effects [7]. Damage models are main tools to quantify stiffness and strength degradation in structures. In general, a damage model is an analytical tool, in which given the loading history (demand) and mechanical characteristics of structure (capacity), an index is calculated reflecting damage in the structure [8]. Such an index is called damage index, DI. Damage models may be local, for structural elements, or global, for a whole engineering structure. Damage indices applications include estimation of losses (human and monetary losses), costs of repair, decision making in post-earthquake assessment (demolition or repair of a damaged structure), disaster planning, insurance costs, evaluation of safety or vulnerability of existing structures and design of new ones[9].

2. Research Materials and Methods Finite element analysis of LS-DYNA computer code and laboratory experimental study have been carried out to evaluate the seismic performance of reinforced concrete. To investigate the prospect earthquake damaged reinforced concrete (RC) column an experimental tests were conducted at Structural Engineering Laboratory, Wuhan University of Technology. All tested specimens were 1/2-scale of typical concrete columns. Each specimen were comprised of a rectangular 250mm×250mm×850mmcolumn connected to two stubs with dimension of 300mm×300mm×500mm and 350mm×300mm×1050mm at the top and bottom level of the column respectively as a representation of beam-column and/or column footing connection. All column specimens were cast with one batch of concrete. The concrete was a mixture of cement, water, sand, and gravel with the ratio of 1:0.458:1.37:2.54 by mass. The mix-design of the concrete was calculated and proportioned according to GB/T 50476-2008.A mean compressive strength of 32.475MPa (standard deviation of 5.25) was obtained for a 28-day concrete cube from standard cubic compression test. For all column specimens, steel reinforcement of type HRB335 (Φ2and Φ16) used as main reinforcement and HPB235 (ϕ6) used for stirrups. From standard tensile test of rebar a mean yielding strength of 397.88MPa and mean ultimate strength of 547.1MPa are obtained for the main reinforcing bar. A mean yielding strength of 363.78 MPa and mean ultimate strength of 445.63MPa are obtained for the stirrups. An elastic modulus of 200GPa and a poisons ratio of 0.3 are used for the reinforcement rebar in this study.

2.1 Load Application An axial compressive load was applied to the top of the loading stub first and kept constant throughout the end of run time. The lateral load protocol is captured from the experimental load protocol used in the test. The maximum displacement at each cycle is inputted as a function of time. An axial compressive and the lateral load were modeled in LS-DYNA as Prescribing displacement motion set to the load bars located on top and side of the stabs respectively as shown in Figure 1.

Fig.1 Prescribed motion and Displacement curve

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2.2 Contact Algorithm CONTACT_AUTOMATIC_SINGLE_SURFACE in LS-DYNA was invoked to model the contact between the concrete section, stabs, supports, and the load bars. This algorithm uses a penalty method to model the contact interface between the different parts. The contact algorithm TIED_SURFACE_TO_SURFACE_OFFSET was used between the concrete column footing and the support bar. This contact algorithm enables to capture the hysteresis response of the column.

2.3 Finite Element Discretization As an initial step, a finite element analysis requires meshing of the model. In other word the model is divided into a number of small element, after loading, stress and strain are calculated at integration points of these small elements (Bathe 1996).An important step infinite element modeling is the selection of the mesh density. In addition, the concrete material model (MAT159-CSCM) used in this study is mesh sensitive. One-element simulation of C30 concrete block were carried out to determine an appropriate mesh density. Mesh size of 20mm were used for the column simulation and the result were much satisfactory than the other trial mesh sizes.

2.4 LS-DYNA Materials Model The longitudinal bars and stirrups were modeled using an orthotropic material model (MAT_PIECEWISE_LINEAR_PLASTICITY), which is Material Type 24, in LS-DYNA. For all column specimens, steel reinforcement of type HRB335 (Φ20and Φ16) used as main reinforcement and HPB235 (ϕ6) used for stirrups. From standard tensile test of rebar a mean yielding strength of 397.88MPa and mean ultimate strength of 547.1MPa are obtained for the main reinforcing bar, and a mean yielding strength of 363.78 MPa and mean ultimate strength of 445.63MPa are obtained for the stirrups. An elastic modulus of 200GPa and a poison’s ratio of 0.3 were used for the reinforcement rebar in this study Material type 159 (MAT_CSCM_CONCRETE), was chosen to represent concrete in this simulation work. The formulation of this material model type was presented in detail in the above discussions. The ability of a material model to simulate real world behavior not only depends on the theory of the material model, but on the fit of the material model to laboratory test data. A rigid material model in LS- DYNA (MAT_RIGID) was used to model the supports and the load application bars in the finite element mode. In LS-DYNA, elements that are rigid are bypassed in the element processing and no storage is allocated for storing history variables. Consequently, the rigid material type is very cost efficient.

3. Analysis Result and Discussion In laboratory experiment for the column specimen the damage index is calculated by the model suggested by Park and Ang. During the damaging phase the hysteresis response were captured. The incremental dissipated hysteretic energy, is calculated from the hysteresis response of the damaging phase of the test is also taken from the hysteresis response as the displacement experienced during damaging phase. is taken from the hysteresis response of the control specimen as the ultimate displacement of the specimen. However, the specimen was tested by cyclic load, this can be taken as an approximate value for the ultimate response. The hysteresis response is presented in Figure 2 .𝛽e is taken as 0.4, as suggested by Jag et al. The damage index

is calculated as ∫

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Fig. 2 Hysteresis response of specimen damage phase

3.1 Load–Deflection Response A comparison of load-deflection curves from tests and finite element analyses to validate the accuracy of the model was carried out .Figure 3 gives the results of the comparison. In general, the results show that the finite element column model does capture the structural behavior of the columns satisfactorily. However, it was observed that the results from the finite element analysis gave a lower capacity after yield than that of the tests. This discrepancy is attributed primarily to the differences between the measured and modeled geometric and material imperfections. It is worth noting that the compressive cylinder values that were used in the analysis of columns may not represent the true values of the concrete columns, due to the size effect and different curing. Furthermore, the FE analysis gave a symmetric response than the test. This can account for the application of the axial compressive load is more uniform than during the test.

Fig. 3. Load-Displacement Response

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3.2 Stress and Strain State All simulated columns behaved in a manner similar to the tested columns up to failure. The progressive response of the control column specimen finite element model at several stages in the simulation can be captured in post processing of the result. The red color on fringe level and in the model represents damage accumulation in the concrete material model. There is considerable damage at the bottom lower fiber near bottom concrete stabs, as expected. Similarly the experimental damage is also near at the bottom of concrete stabs as depicted in the Fig.4.

Fig. 4 Comparison of the tested column and FE model failure mode

4. Conclusion Earth quake is catastrophe for human life and engineering structures and being a cause of huge economic losses. Reinforced concrete has been a widely used as construction material in many structure members including floor, wall, roof, water structure, joint and etc. LS-DYNA is a powerful finite element dynamic analysis to model the reinforced concrete prone to earthquake and can evaluate the seismic performance of the reinforced concrete. Laboratory experiment of seismic prone reinforced concrete helps to evaluate seismic performance and the output is used as in input for finite element analysis in LS_DYNA. The output shows that the finite element analysis reinforced column model does capture the same behavior of column shows in the laboratory experiment. The significant damage occurs at the bottom of the reinforced column which is very difficult for maintenance. Therefore seismic is a serious problem that the concrete structure to be failed any time during seismic occurrence.

Acknowledgement I would like to appreciate the dedication of National Natural Science Foundation of China for the budget allocation under the grant award No.51308429 to be successfully carried out the research work.

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References [1] O.Melchor-Lucero and C. Ferrgut, “Earthquake Damage assessment of Reinforced Concrete Members Using an Expert System”, Eleventh World Conference on Earthquake Engineering, 1996. [2] J.Ogawa, J.Shibuya, and M.Hoshi, “Earthquakes Damage Evolution of Reinforced Concrete Column Earthquake Engineering”, Tenth World Conference, 1992. [3] N. Banthia Nandakumar and N. Boyd,” A Sprayed Fiber-Reinforced Polymers: From Laboratory to a Real Bridge,”ACI Concrete International,2002. [4] M.N.Fardis and T.B.Panagidtakos, “Hysterstic Damping of Reinforced Concrete Elements”,Eleventh World Conference on Earthquake Engineering, 1996. [5] M. Bazan, and M. Sasani, “A New Damage Model for Reinforced Concrete Elements”, 13th World Conference On Earthquake Engineering Vancouver,B.C. ,Canada ,Paper No.2846,2004. [6] F. C. Filippou and A. Issa,” Nonlinear Analysis of Reinforced Concrete Frames under Cyclic Load Reversal”, Earthquake Engineering Research Center College of Engineering University of California, Berkeley, 1998. [7] B. Behrouz and R. Hamid, “Post-earthquake Fire Performance-Based Behavior of Reinforced Concrete Structures”, J. Eq. Str.5 (2013)379-394. [8] Y.Burak,, S. Erkut and S.Teoman, “Seismic Response of Buildings During the May 19, 2011 Simav,Turkey Earthquake”, J. Eq. Str.5 (2013)343-357. [9] L. Carmine, S. Gaetano, and M. Enzo, “Seismic Response of Masonry in Filled RC frames: Practice-Oriented Models and Open Issues”, J. Eq. Str. 6 (2014)409-436.

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3D Model Identification using Histogram Normalization with Conformal factor Ruichen Jin1, Jongweon Kim2 1

Department of Copyright Protection, Sangmyung University, Seoul, Korea Department of Contents and Copyright, Sangmyung University, Seoul, Korea

2

Abstract: Various people created and upload a large number of 3D models on website. For protecting the copyright of 3D contents, the technologies for 3D model identification then became necessary. In this paper, we present a method using conformal factor to extract the node of 3D model’s topology and combine the data of vertexes histogram of projection from center of sphere to the surface of sphere reference to the latitude and longitude. For increasing the robustness in various transform such as scaling, rotation and deform, we normalize the size of radius bounding sphere and histogram. After this process, we get progressive results in 3D model identification. Keywords: 3D model, identification, Spherical Coordinate System, conformal factor,

1. Introduction Due to the expiration of patents related to 3D printing technology, people are more interested in 3D printing. Various industries pay attention to the technology of 3D printing. Many people create the 3D models and share it on the internet. We can find 3D model easier that we want. 3D printing models also has copyright. For protecting the copyright of 3D printing model, we need higher technology to retrieval and identification. For retrieving 3D model, it has several concepts. Such as previous algorithm with 2D view-based use the several view points as query [1-2] and topology based method to identification [3].

2. Proposed Algorithm We shall briefly introduce both of the related works concepts and then describe the proposed combined scheme.  Step 1: Normalize the 3D model using minimum radius bounding sphere. It is a mathematical problem of computing the smallest circle that contains all of a given set of vertexes in the Euclidean plane. The corresponding problem in n-dimensional space, the minimum bounding sphere problem, is to compute the smallest n-sphere that contains all of a given set of vertexes. It was initially proposed by the English mathematician James Joseph Sylvester in 1857[4]. The smallest-circle problem in the plane is an example of a facility location problem (the 1-center problem) in which the location of a new facility must be chosen to provide service to a number of customers, minimizing the farthest distance that any customer must travel to reach the new facility. Both the smallest circle problem in the plane, and the smallest bounding sphere problem in any higher-dimensional space of bounded dimension, may be solved in linear time. We set the sphere of radius as 1 unit to normalize for robust in scale attack. The sphere must be minimum includes all vertexes. Pose normalization methods can be robust to rotation attack. Pose normalization methods

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that are based on principal component analysis of the 3D objects. The PCA algorithm is based on the computation of 3D object moments and estimates the principal axes of a 3D object that are used to determine its orientation. Fig. 1 shows pose normalization after the minimum radius bounding the human 3D model.

Fig. 1: Minimum radius bounding the human 3D model.

 Step 2: Extract skeleton node by conformal factors. The discrete conformal factor for a 3D mesh, which is used as a non-rigid shape descriptor[5,6]. The mesh surface area around a vertex, which is computed as Pseudo-code for the calculation of the surface area of region of vertex on an arbitrary mesh. The triangular area of face based on a standard estimation method (Heron’s formula). The surface area contribution of a single non-obtuse triangle. A graph with node can be used as a topological map that represents the skeletal structure of an object with arbitrary dimensions. Using the generated node descriptor to obtain the correlation between the models. Assign the largest weighted on the first adjacent nodes and decreases the weighted as distance of node. Using skeleton node by conformal factors can be robust to non-rigid models. Fig. 2 shows two 3D models which extracted skeleton nodes by conformal factors. The right model is difference for being deformed and cut with left model. The extracted node shows the same structure exclude the parts of head cut and it can be robust descriptors with non-rigid model.

Fig. 2: Extract skeleton nodes by conformal factors.

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 Step 3: Calculate the histogram of vertexes of model reference to the latitude and longitude. 3D models are included in tens of thousands vertexes coordinates normally. We can use the distribution of these vertex coordinates as descriptor effective and simply. Fig. 4 shows the axis coordinate system and the ) spherical coordinate system. Covert axis coordinate system ( ( ), ( ) ( ) √ ( ), ( ), ( ).

Fig. 3: Axis coordinate system and the spherical coordinate system.

We can understand that such means the projection from centre of sphere to the surface of sphere, classify the vertexes of model reference to the latitude and longitude. We classifies a vertex and make histogram depending on latitude and longitude with after pose normalization model. With each x -axis, y -axis, z –axis as main draw we can get the histogram is shown Fig. 5. It takes short time to identification the letter as an engineer calculates the model is simple.

Fig. 4: Projection the model to the surface of s sphere

Fig. 5: Histogram of vertexes of a 3D model.

 Step 4: Calculate the total similarity Through the values of calculating each similarity using the both descriptors of the aforementioned, we rank the results that multiplied two values of similarity.

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3. Experiments and Results To evaluate the performance of the proposed method, we have construct a features dataset from 3D models of the SHREC’15. The PC specifications are Intel® Core™ i7-4790 [email protected], RAM 8GB, OS Win 10 Home.

Fig. 7: The Result 1 of 3D model identification.



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Fig. 7, 8, 9 shows result of 3D model identification methods that we proposed. Retrieval the model with a query model, it spend about 7 to 9 seconds. We use the 120 models to build the database. From the Fig. 7, 8, the query model can identification the 3D models include itself. Fig. 9, the one of ant models low rankings because of the ant legs are attached. In this case, the extract skeleton nodes by conformal factors are dissimilarity with the query model’s extracted skeleton nodes.

4. Conclusion In conclusion, we have introduce a new effective method for 3D model identification. It use using conformal factor to extract the node of 3D model’s topology and combine the data of vertexes histogram of projection from centre of sphere to the surface of sphere reference to the latitude and longitude. Using skeleton node by conformal factors can be robust to non-rigid models. The descriptor using histogram of vertexes of model with coordinate system are simply calculate, it has advantage of increasing searching time For increasing the robustness in various transform such as scaling, rotation and deform, we normalize the size of radius bounding sphere and histogram. After this process, we get progressive results in 3D model identification.

5. Acknowledgements This research project was supported by Ministry of Science, ICT and Future Planning in 2016.

6. References [1] S. Chen, B H. Shum, R. Szeliski, “Construction of panoramic image mosaics with global and local alignment,” International Journal of Computer Vision, Vol.36, No.2, pp.101-130, 2000. [2] C. Tang, “Self-Calibration for Metric 3D Reconstruction Using Homography,” IAPR Conference on Machine Vision Applications, pp.86-89, 2007 [3] Z. Zhang, “A Flexible New Technique for Camera Calibration,” IEEE Trans. on PAMI, Vol.22, No.11, pp.1330-1334, 2000. [4] J.J. Sylvester, “A question in the geometry of situation,” Quarterly Journal of Mathematics, 1857 [5] M. Ben-Chen and C. Gotsman, “Characterizing Shape Using Conformal Factors,” Eurographics Workshop on 3D Object Retrieval, 2008 [6] K. Sfikas, I. Pratikakis and T. Theoharis, “Non-Rigid 3D Object Retrieval using Topological Information guided by Conformal,” The Visual, vol. 28, pp. 943-955, September 2012.

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Towards Environmental Sustainable Neighborhoods in Riyadh City Akram.R.Ahmed1 and Khaled Abdullah Al-saud2 1

Postgraduate student Assistance professor King Saud University Riyadh, K.S.A 2

Abstract: The neighborhoods is the most important places to practice living activities, which aims to achieve a perfect environment, The environmental sustainability in the neighborhoods of one of the most important elements of the renaissance of peoples and the continuity of resources and preservation of the environment, The great depletion of the resources of fossil energy in the Riyadh city and not to take advantage of the surrounding local resources which increase carbon emissions rate and other environmental problems in the region, That is the research problem. So this paper is interested in leading the design of residential neighborhoods environmentally sustainable carbon-free and self-contained. The study aims to show the important issues to get to the residential neighborhoods sustainable far from the negative environmental effects with the participation of community, and create a valid clean environment to live. Study hypothesis depend on possibility of achieving residential communities environmentally sustainable by taking advantage of past experience, and diversity to find alternative solutions. Study is based on comparative analysis through the analysis of the most successful case studies in the world and benefit from past experiences, opportunities, challenges, pros and cons to get the general framework can be applied to neighborhoods to reach the highest possible extent of sustainability.

Keywords: Sustainable neighborhoods, urban sustainability, Riyadh neighborhoods, Environmental sustainability.

1. Introduction Population explosion today globally of the biggest problems that require urgent solutions to accommodate the rapid population growth is considered, is the residential neighborhoods of the most important places for the exercise of various household activities, and highlights the importance of embracing many of the behaviors and activities and various entertainment, security, and other, which ultimately aims to achieve appropriate for residents of the environment All environmental, economic and social aspects. As a result of climate change and loss of biodiversity and pollution of the environment these reasons lead to the urgent need to increase the sustainable development by encouraging and enabling sustainable lifestyles of the population in urban areas and through the promotion and development of neighborhoods to get to the sustainability of being considered the nucleus of the cities, and if it is to find environmental solutions for the living, it means Overcoming a large part of the environmental problems in the city. And it should meet the residential neighborhoods today all living requirements according to less economic and design level preserves the environment and working to achieve all the social opportunities, and considers sustainability in the last decades of the most important topics prevalent in all areas as conserve resources for future generations, and is the environmental sustainability of the most important pillars of sustainability three (environmental-economic-social) The fact that concern for the environment to achieve sustainability as a system runs on automatic investigation of many aspects of economic and social sustainability, He added the recent demand in the construction of more housing, which led to the emergence of new residential neighborhoods a very fast pace, and drain neighborhoods designed in the usual way a lot of the core

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cities such as energy, water and increase waste resources, and how long they will be around these neighborhoods deplete resources that increase the economic burden for the country, leaving behind a lot of damage environmental, and therefore sustainable neighborhoods emerged as an idea and realistic to reduce the depletion of the country's resources, and self-reliance on energy, water and waste management and transport system under sustainability.

2. The problem of the study: The concept of sustainability in urban communities is a mindset and applied, and seeks to develop and debug the way normal currently prevailing for the design and implementation of units nearby, including the way the usual contain many of the environmental and operational problems and social and economic as well, and damage to the environment and the depletion and waste of resources, so the concept of neighborhoods or sustainable communities working to transfer the design and planning practices of the current form to another formula more sustainable, and that by raising environmental performance and optimal utilization of natural resources, reduce pollution, and increase the fresh air rate, and reduce energy consumption, and take advantage of environmental resources, and management and other waste, and gain access to environmentally sustainable architecture, and therefore are considered sustainable communities are not only places of seeking to achieve environmental integration which in turn achieves a large part of social integration less economic cost and reduce wasteful consumption and take advantage of the ocean, to reach the living efficiency, and become many neighborhoods among cities threaten the ecological balance in the world, and is considered it is cities responsible for 80% of the emission of greenhouse gases (GHG) greenhouse (Condon, 2010). At the local level suffers neighborhoods in Arab cities many of the environmental problems, on many levels start to drain generated from fossil fuels and water scarcity and increasing waste proportion of energy without the benefit of them, and statistics indicate negative slope towards the depletion of environmental resources, for example based on what came in the annual report of the Electricity Regulation and Cogeneration in Saudi Arabia energy consumption in residential buildings amounted to 38.4% of the total production of domestic energy, and the increasing demand for electricity rate of 9 percent annually. (Report of the Electricity Regulatory and Cogeneration Authority .2013) It turns out that per capita solid waste in the Gulf Cooperation Council (GCC) is among the highest worldwide, with a growth rate of 10% per year, is the highest at the global level. The Kingdom of Saudi Arabia's share of the solid waste in the Gulf Cooperation Council (GCC) are the highest and by as much as 60% of the total solid waste in the region. And that the amount of waste in the Kingdom during the year 2013 up to more than 12 million tons, and the average per capita production of municipal waste is about 1.28 kg per day, rising to 1.4 kg in major cities and at least 1.1 kg in medium-sized cities, while up to 0.7 kg per day in small towns and villages The report also pointed out that organic waste account for over 40% of municipal waste produced annually, followed by paper and cardboard waste by 20%, then the plastic by 15%, followed by metal and glass waste, textile rates ranging from 4 to 7% per annum (Ministry of Municipal and Rural Affairs 0.2014). And in this sense must intensify efforts in waste recycling process to take advantage of in an environmentally and economically both. The Kingdom of Saudi Arabia from the top five countries in the world suffer from water scarcity, and the desert environment of the queen had to deal with water as the first supplier of the natural resources, the per capita water consumption rate in the city of Riyadh more than 315 liters / day and higher than the rate of consumption the world of the individual who is in the range of (150-200) liters / day (Ministry of Electricity and Water, 2007) The residential neighborhoods of the biggest areas consuming local resources being accommodate larger residential areas and contains many different activities that require different living needs, and the trend towards the conservation of resources and reduce the consumption ratio and promote the principland the search for solutions proposed, and look at the experiences of other countries to solve such problems and improve the local environment and access to the highest possible level of household services within residential neighborhoods compared to less depletion of natural resources and the preservation of the surrounding environment. And research tes of sustainability and therefore had to take into account all the previous negative issues the problem lies in "The existing residential neighborhoods in fall short of achieving environmental sustainability requirements of Arab cities, and the need to diagnose the current reality, and the search for opportunities to turn

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it into environmental sustainability stage through the achievement of the most important sustainable environmental resources, a self-sufficiency in energy demand."

3. Importance of the study: The study of the sustainability of the residential neighborhoods of the most important studies that have environmental, economic and social dimensions, which is working to raise the standard of living of the individual is far from the massive depletion of natural resources and achieve the preservation of the environment, and that the interest in such studies because positive impact on peoples' level of individuals and institutions, and lies the importance of the study in: • Creating clear principles applied to the process of re-designing residential neighborhoods a way that reduces energy consumption, and make it more convenient to live. • Translation seeing communities zero energy into reality. • Produce clean domestic environment is working to reduce environmental pollution and emissions of carbon gases. • Display realistic vision of neighborhoods versus self-contained reality is full of random, waste, and attrition. • Open a new initiative approved by the competent authorities for the application of urban design in residential quarter's way that reduces energy consumption.

4. Methodology: This study reviews the examples similar to the units next to sustainable around the world, some made them energy self-sufficiency, and depend on the methodology comparative analysis by limiting the successful examples worldwide, and analyze successful and sustainable issues for each model and methodology solutions provided, and to highlight the pros and cons, threats and challenges, benefits, and then conduct scientific comparison between all selected examples, to get out a broad framework to achieve the goals of the study.

5. Objectives of the study: The study aims to find the principles and directions enough to design new neighborhoods and create sustainable local environment more livable. It also aims to re-use these principles in the re-design of existing neighborhoods and renew the vision of sustainable older neighborhoods to become responsive per environmental, social and economic requirements. And cut all the negative environmental practices in neighborhoods to reduce negative impacts on the environment and reduce carbon emissions. The goal of the study to go out a broad framework and many of the principles and guidelines for the design of sustainable residential neighborhoods, and to find solutions to the difficulties in reviving the list of sustainable residential communities according to previous experiences.

6. Study hypothesis: The possibility of achieving a zero energy residential areas by applying systems and sustainability strategies with the benefit of contemporary experiences. - The revival of the list of sustainable benefit the specialists to take advantage of clean environmental issues and benefit from the principles used process analysis, design and revive the zero-energy check all living requirements.

7. Literature Review: Presented a study (Palma and other, 2013) towards a sustainable green strategy for social neighborhoods in Latin America: the case of social housing in Merida, Yucatan, Mexico, which aims to propose green and sustainable strategies to reduce greenhouse gas emissions (GHG) associated with the consumption of energy in the neighborhood Merida (Merida, Mexico), Mexico. The environmental strategies in terms of the provision of green spaces within neighborhoods, and technology in terms of the efficiency of household appliances, which gives savings in energy consumption, the study used a survey method, and the process of assessing the life of the 58

building cycle, the study collected data on the level of energy consumption in the neighborhood was to make precise calculations for consumption and calculating the amount of greenhouse gases in accordance with the evaluation of the building to calculate the amount of carbon emissions life cycle, the study proved that it can reduce 67% of carbon emissions, of which (34%) are avoided by environmental technologies, and (24.5%) by green spaces, and (8.4 %) by providing dedicated to the cultivation of the necessary vegetables for residents of the neighborhood flats, were savings calculated in carbon emissions rate to another rate through transport vehicles and carbon emissions of which move, and carbon reduction rate in the neighborhood that contains (1903) housing units is (1696) tons annually. While the study (Luederitz and other, 2013) about a systematic review of the guidelines for the development of sustainable residential neighborhoods, some trends raised and principles for the development of sustainable development in urban neighborhoods, and the study is based on quantitative presentation of the principles of neighborhood development depending on the literature of the study, however, the study considered that it is still These principles are not clear to participate and move towards sustainability, the study relied on a survey method of the previous literature that displays directions to achieve urban sustainability in the neighborhoods, was first: identify promising approaches that offer principles close to the core of sustainability criteria, and secondly: to provide starting points for the development of a strong set of principles By combining literature and tested, and thirdly: aspects of sustainability that have been covered adequately been in the spotlight Based on the results, and finally, outlining a road map to encourage more research to develop a sufficient principles for the development of sustainable neighborhoods And offered study (Azmi, 2012 & Abdul kareem) about the implications to walk on foot to enhance the sustainability of residential neighborhoods, said that the phenomenon of urbanization in the revival of cities have resulted in an increase in the use of motorized vehicles to navigate, and that the culture of urbanization has become using cars even in movement within the neighborhood, and that the external environment in residential neighborhoods has a significant role in promoting foot traffic instead of using motorized vehicles, and the study was based on exploratory approach through direct observation of the proportion of the population who have mobility on foot, it was chosen Putra Jaya district (Putrajaya) inspired Shah Alam (Shah Alam) and are within 25 km south from the Malaysian capital of Kuala Lumpur, in addition to the personal interview certain samples from residents of the neighborhood, and the number of the sample (50) people, who are, who have a key role and doth professional more Kmkhtti cities, architects and Landscape Architecture all categories ( academic, practitioner), was conceived (38) of them negative and 12 positive person, and that the district needs to promote sustainable ideas to encourage the mobility to walk away, and the study concluded that the footpaths in the case study is still lacking to encourage people to walk , and it must be taken into account when designing neighborhoods footpaths and misleading and increasing forested, and work on the compilation of urban services to give comfort careerism, and all these measures increase the sustainability of residential neighborhoods. And the study (Choguill, 2008) on sustainable neighborhoods develop presented the characteristics of units sustainable neighbors of all social, economic and environmental aspects, and the most important economic characteristics are planning in a sustainable way to achieve lower cost of transport and infrastructure, and achieve movement within the neighborhood to walk on foot, In order to justify the social sustainability must be a residential neighborhood less than a 3,000-strong enough to allow the free exchange between the members of the community, and public participation in their living environment decisions, and on environmental sustainability and landscaping would prefer to be next to the elementary school and to promote social link between mothers and children , and adopted the study to see sustainability in the revival of Riyadh shows the use of cars excessively between neighborhoods within the city of the largest dimension of the problems of environmental sustainability, and that the lack of green spaces within neighborhoods reduce the social networking, and distribution neighboring Services pedestrian traffic hinder nor allow for children to walk on foot towards their primary school, and that many countries around the world working to establish an integrated revive local services to reduce the use of transport and increase economic sustainability.

8. Environmental sustainability: Sustainable word in Arabic means causing continuity or follow-up and continuing thing. Defines sustainability as Brundtland Report (Brundtland, 1987) "group of the living requirements that meet current needs without wasting the ability of future generations to meet their needs and to live with dignity in the same capacity available for the current generations" and this report may put forward related to sustainability on a global scale 59

ideas by the Minister as Environment Dane, and after World War II was necessary to achieve development in all areas without referring to the importance of sustainability, then later emerged the concept of sustainability linked to the knowledge economy, which has been used to express the ability of the community the ability to economic growth, and then expanded the concept to include all the cognitive and cultural aspects, In the nineties of the last century concept appeared stronger at the international and global level were put forward the concept in the Rio de Janeiro Conference in 1992, and adopted put the concept of the three key aspects is the economic side, social, and humanitarian, it has been linked to all aspects to improve the standard of living of the human being in all aspects of life, and today the concept has become more flexible, and worked hard a lot of interested people and specialists in the field of sustainability to become a basic necessity in most aspects of life (al-Farra, 2010).

9. Sustainable buildings: That sustainable buildings are good and convenient method of building a highly efficient and simulates the surrounding environment, because the architecture is still and will remain a major part of the natural environment. And that sustainable building is the practice to maximize the efficiency of buildings and locations in the use of resources, energy and water, and at the same time reducing negative impacts on human health and the environment along the age of the building. That the building-according to the definition of architectural Yang-phrase for both sides: the first is the physical configuration and is in the temple, construction and shape, and the other is the functional aspect and is the functional and operational processes that verify the continuity of operation of the building throughout his life, and both sides make the building a close relationship with the natural, and that The building is similar to the organism being fed on the surrounding water and energy and natural resources and pronounces it outputs (Yeang, 1999). Therefore, sustainable buildings that reduce inputs that are obtained from the natural environment, such as energy, materials and water, and is working to take advantage of, and at the same time working to reduce the output of those buildings in the natural environment, which includes waste and pollutants. Sustainable buildings today is nothing but a link between today's architecture and building the future according to the environmental, social and economic contexts, but represent environmental sustainability in buildings essential foundation for achieving comprehensive and sustainable development, and at the level of buildings only there are many issues to achieve environmental sustainability, but there was no global consensus to determine a uniform issues, there are varying the number and nature of cases achieved environmental sustainability, for example, put the American Society for Testing and Materials ASTM standard guide the general concepts for sustainability in buildings, and practical application of the principles of sustainability, either Leadership in Energy and the Environment "Lead" designs LEED minimum target is to design, construct and operate new and existing projects on less energy, water and resource consumption, and produce less waste and provide a healthy environment for residents and visitors, and reducing the impact of the project on the environment during its life cycle. And issues of environmental sustainability are sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality and creativity and innovation in design. This standard was developed the US Green Building Council USGBC, was to begin its implementation in 2000. And the national standards for green buildings ICC- 700 2008 has placed compliance with quality standards, in construction or renovation and showed the issues that achieve environmental sustainability of buildings are: the development of the construction and location of land, and energy efficiency, water use efficiency, efficient use of resources, and indoor environmental quality and homeowner education. And the earth Earth Craft House craft house seeks land craft program to respond to the needs of consumers and touched on the set of issues, namely: the proper planning of the site, and efficiency in the design, and the use of building materials and resources, water conservation, and energy efficiency through the building envelope and systems and devices energy-saving lighting, health and air quality in indoor, construction and durability, convenience and affordability and waste management. The Building Research Establishment Environmental Assessment Methodology BREEAM addressing key sustainability issues that arise when constructing a new building using nine the following major categories: administration, health, and well-being, energy, transport, water, materials, waste, land use, environment and pollution. Clear from the foregoing uneven number of issues of environmental sustainability in buildings according to standards have been taken from the views of environmental organizations specialized for that, but the thrust of

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this study is interested in the achievement of environmental sustainability in residential neighborhoods, so it will be displayed what sustainable residential neighborhoods, and the review of all the issues that achieve sustainability in the following lines.

10. Sustainable Neighborhoods: Sustainability as a concept can be applied to local and international wide levels, and was officially launched sustainable neighborhoods ideas through drawing up plans for the implementation of sustainable development locally, and through the creation of communities and sustainable cities, and together with sustainable neighborhoods can sustainable development application but sustainable cities (Campbell, 1996) the fact that neighborhoods It is the nucleus of the founding of cities, and the cities of success is the success of the residential neighborhoods where. And the neighborhood or sustainable rally is the one who meets all the sustainability requirements in the environmental, economic and social fields for the benefit of present and future generations, and is designed to create a healthy environment and to maintain the economic level, and the achievement of social justice, and the promotion of public participation in planning and implementation, and identify sustainable communities network of sustainable neighborhoods as "citizen engagement and institutions to put the principles of sustainability and put up a collective vision for the future, and that apply an integrated approach to achieving environmental, economic and social objectives. " Sustainable communities are the vicinity of integrated to achieve a variety of living practices, a place where people aspire to, whether in the present or in the future, and address the diverse needs of existing and the resident population in the future, and to achieve high quality in healthy living, and providing equal opportunities and facilities for all the inhabitants (Bristol, 2005). It defines sustainable communities Institute (Institute Sustainable Communities-ISC) sustainable neighborhood as "a community to achieve economic, environmental, social, health, flexibility, and meets all the objectives of sustainability without harming others, and to highlight the long-term perspective to achieve current and future needs." In other words, "sustainable communities manage natural, human and economic resources to meet current needs, equitable and provide the necessary materials needed for future generations." Established by the United States government in 2009 Partnership for Sustainable Communities (PSC) program to promote sustainability at the neighborhood level, and to join in this program and the US Housing and Urban Development Ministry of Foreign Affairs (HUD), the US Department of Transportation (DOT), and the US Environmental Protection Agency (EPA) and aims program to help communities at the national level and improving multiple options for access to housing, transportation, living affordable while protecting the environment. This partnership working towards achieving sustainable communities in coordination with housing, transportation, water, and investments in infrastructure to keep the neighborhoods, and drive people to live and work in the same place to reduce pollution. The program includes six principles are: (1) provide more options for flexibility of movement (2) promote the fair affordable housing. (3) The promotion of economic competitiveness (4) support local communities' menu (5) coordination and take advantage of federal policies and investment (6) evaluation of the communities and neighborhoods. However the program sustainable society is defined as "the place where people can live closer to their jobs or easy access, and access to jobs in the same area on a larger scale thanks to public transport and soft." They include sustainable communities a variety of accommodation types, which is located near the workplace, schools, public parks, and amenities, making it comfortable for walking, and the use of a bicycle, and ease of transit, and ease of driving short distances to daily destinations (Partnership for Sustainable Communities, 2010)

11. Sustainability issues in Neighborhoods: There are several key issues to promote environmental sustainability in residential neighborhoods, and states (condon, 2010) that there are seven basic rules to achieve sustainable residential communities and is the result of 25 years of thinking about finding the best ways to strengthen neighborhoods towards sustainability, namely: 1. Restoration of tram (streetcar): So as to enhance the transport level of the neighborhood and even the workplace or other residential neighborhoods, and is considered one of the most minute elements of sustainable development. 2. Interconnected street system design: Check the safe and convenient transit and provide a short trip neighborhood income, and reduce the use of vehicles, and promote walking and bicycle use.

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3. The establishment of commercial and local services in a way that touched the neighboring transit and foot traffic, and the development of schools, places of no more than five minutes on foot: And is one of the most important destinations to meet away from the use of vehicles neighborhood requirements, and the fact that children are the most crossovers for schools, the most widely used for walking to navigate, and therefore should not be less Qatar school site in the residential neighborhood about 10 homes. 4. To identify good and close functions of houses and dwell affordable: The majority of the new jobs in the United States and Canada are compatible with full community circles. 5. Provide a variety of housing types: The design neighborhoods for low-income communities in a dedicated them, reduce the demand for other housing, so the diversity of housing at all levels reduces the movement and access problems. 6. Establish a system to link natural areas and parks: Maintaining clean water, streams, rivers, and should be reconsidered in sewage treatment in the neighborhoods. 7. The investment is less weight, and more sustainable, and cheaper, and in smart infrastructure: Auditing standards in the municipal facilities that drain the development and maintenance of high costs and is working to destroy the environment, so smart solutions for infrastructure and more sustainable and cheaper is required to achieve sustainable strategies in the neighborhoods. (condon, 2010). All the rules described above is one of the issues that must be introduced and not be overlooked, which covers the basic needs for sustainability of a broad planning perspective, but the other hand there are many residential neighborhoods that have achieved a high level of environmental sustainability through the creation of sustainable ecological solutions and utilization of natural resources and the preservation on the environment, environmental sustainability and contain many of the issues that contribute to reducing the waste of natural resources and non-optimal use of resources.

12. Successful models for sustainable districts: Neighboring Hammarby (Hammarby Sjöstad) is one of the -More neighborhoods sustainability in Sweden, was the establishment of the neighborhood on an industrial site south of Stockholm, Sweden, has been redevelopment of the city in a sustainable way in 1990 generally being the host of the Olympic Games, but has not hosted decided the city to walk behind the development of communities sustainable, hence the idea of attention and starting to achieve the revival of a sustainable environmentally friendly. Of the living area of 250 hectares and is home to over 26,000 people and faithful to 11,000 housing units, the project seeks to achieve sustainability through seven issues: the optimal use of land use, improve energy use, water management and sewage treatment, a good system for waste collection, movement and access efficiency, remove the contaminated soil, and the use of local building materials sustainable and harmless. And is the optimal use of land in a nearby Hammarby responsive to all social and economic requirements, which have been allocated approximately 15% of the site area of 35 commercial zones employs approximately 10,000 workers or approximately 35% of the total population. It has been improved use of energy through the heating and cooling areas using thermal station for heating from waste incineration, also used for sewage treatment, and are to take advantage of the cold sewer cooling water through the cooling system in the neighborhood, and either biogas and fertilizer capacity are human waste and food waste for analysis Using bacteria and converted into biogas is used in city buses running. The most water management and sewage treatment to benefit from the technology through the implementation of processing sewage capacity of up to 62

600 people / h station, used the station only to sewage treatment to reduce pollution district level, biogas extracted from the sewage plant is to take advantage of the result of analysis fertilizer local gas vital also runs the 1,000 units of the kitchens in addition to the neighborhood bus driver, and are rain water treatment was performed private channels with floodwaters from the roofs of buildings and water resulting from the melting of ice in the courtyards and streets of the neighborhood, and then move to the treatment plant and then pour in lake. The neighborhood (Bo01) in Malmo (Malmo) in Sweden, which was created on the waterfront in Vastra Hamanan and reach the site of 18 hectares, and the site is a landfill 100 years ago, was nominated as a Residential against the backdrop of the international exhibition for the development of European cities and in the name of the city of tomorrow (city of tomorrow), has focused on all the environmental, social and technical sustainability ideas, was the construction of 500 homes in addition to the social and commercial facilities and halls display units and office buildings and the neighborhood. The city administration has been focused on in this neighborhood for the highest rate of environmental sustainability and many of the environmental issues such as energy treatment has been to rely on alternatives to many of clean energy systems, has been the demand for heating energy coverage through groundwater as a source of energy for heating and cooling, and working heat pump to raise the ground water temperature of 15 to 67 degrees Celsius to be utilized and pumped to the network neighborhood heating, and provides the network 85% of the heating required energy, and is compensated for the remaining 15% by putting solar panels on the roofs of nine buildings area of 1400 m2, and also there 200 m 2 of discharge pipes complexes high-efficiency, were provided with electric-powered site through solar energy sources, wind is generated 1% of the power available through solar photovoltaic, and 99% of the wind power plant, which lies on the site three kilometers, were used systems intelligent software in house. The neighborhood is aimed at creating a sustainable clean environment through movement and access to the city level solutions, and organic waste is utilized in biogas generation (methane) that is running buses between the neighborhood (Bo01) and the rest of the neighbors and the city center neighborhoods, either navigation systems inside neighborhood depends heavily on bicycles, and there is a great acceptance of all residents of the neighborhood to be used to achieve safety in the neighborhood in terms of risk vehicles, and to achieve environmental sustainability and reduce carbon emissions, the City that works clean energy buses are considered (biogas) is the best alternative in the event of fluctuations Weather and lack of possibility of using bicycles. And the unit next to (Vauban) in southern Germany, to the south of Freiburg (Freiburg city center) was built on the site was formerly an old military base in 1996, and has a population of 5,000 people, with 2,000 housing units, the main objective of this project is the implementation of the neighborhood in a way collaborative and participatory to meet multiple requirements such as environmental requirements. (Energy, and public transport, heating system, and green areas) and economic requirements (balance between work areas and residential area, a central shopping centers in the neighborhood) and cultural requirements (neighborhood center for social interaction and the establishment of social events and cultural). And designed all the houses and buildings in the neighborhood to achieve the lowest consumption of energy, and the generation of renewable energy in the neighborhood through solar cells, providing 65% of the required building energy, and the housing of the central heating that works burning wood chips 80% of card terminal heating and by 20% of natural gas.

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Vauban neighborhood in (Bo01) in Malmo southern Germany: Sweden:

(Hammarby Sjöstad sustainable) Sweden:

TABLE I shows a summary comparison of the previous case studies

Pure Energy

Transportation

Waste management and sanitation

Access to clean energy by 100% and energy heating and cooling are the result of the burning of waste. Energy and organic material used as a gas vital to the operation of city buses.

varied mobility opportunities and all sustainable, by encouraging the use of bicycles and neighboring rail network linking the use of ferries and boats aquatic bio-fuels, and the reduction of vehicles through the development of a participatory system

Self-sufficiency in the production of 100% clean energy. Heating energy is generated from groundwater. Electric power generated from wind turbines and photovoltaic cells

Neighborhood bicycle network is used to move around the center of the neighborhood. The buses neighborhood methane gas to move between the main transport network and when bad weather

Biogas produced by the sewage plant is used to run 1,000 units cooking. And waste suction systems underground reduce environmental pollution and promote the utilization of waste and recycling. It has been developed to reduce water consumption intelligent systems. Put kitchen waste grinding system. Lay waste suction system. Develop a system of waste sorting and recycling.

The electric power generated from solar cells by 65%. This is the generation of heating and cooling energy from the burning of trees and leaves by 80%, and 20% of natural gas

The decision was short-design of roads in the neighborhood. Trams and main means of linking the city center, passing near the neighborhood. The use of bicycles in the neighborhood. Encouraging participatory system for the use of vehicles.

‫ـــــــــــــــــــ‬

And to benefit from the global models that a large proportion of the success achieved and exceeded many of the challenges we will look now to the key issues of environmental sustainability in residential neighborhoods, namely:

A. Pure Energy: You need to know the basic aspects to cover the needs of the energy in residential neighborhoods, and is this the case of the most important issues of environmental sustainability in residential neighborhoods, the fact that fossil energy is not an alternative has been depleted in the coming years, as well as negative returns of greenhouse gas emissions () and environmental pollution, and increase air pollution within neighborhoods, and can take advantage of solar energy as alternative energy to generate electric power operating within the neighborhoods, and to cover the demand for electrical power required can use wind power to generate a voltage greater to run air conditioning units and devices with high electrical capacity, and are benefiting from ground power (Geothermal) or energy seas to cover the demand for heating and cooling.

B. Neighborhood Mobility: Of the most important living requirements in residential neighborhoods to achieve mobility and transit efficiency in the neighborhood on the one hand and between neighborhoods and places of work of those who dwell on the other hand, there is a positive relationship between land use and efficiency of the movement to reduce the dwell movement and reduce the demand for transportation daily to perform their jobs, and that the basic considerations in the process of residential neighborhood that achieves integration and interdependence between local and commercial jobs, schools and short distances reduce the demand for transportation and can navigate on foot, and attention to the infrastructure of the means of alternative transportation descriptive carbon emissions like buses that operate bio-gas and electric vehicles and bicycles promote the achievement of sustainable mobility environmentally and planning not to rely on transportation fossil energy pollute the environment and reduce the energy demand for mobility.

C. Waste Management: Implementation of the most important technological innovations in waste management is one of the one of the common means of waste management in technological promote preservation of the environment, and turning waste into a source of clean energy in the neighborhood, use of suction antenna systems buried underground reduce waste exposure above the soil surface of biological agents that increase the spread of Mosquito health and pollution, and that the process of sorting and analyzing the waste is beneficial bug man to take advantage of recyclable for remanufacturing waste, inorganic waste non-recyclable to be utilized by burning and take advantage of thermal energy for heating, and organic waste that can be used to generate biogas which is used in operation of public and private transport vehicles, and benefit from it in cooking. 64

D. Water management and Sanitation: Good management of waste water is considered the most successful, especially in water-scarce areas to be to take advantage of gray water, wastewater and utilized for irrigation, and to benefit from solid to produce biogas waste, and should take advantage of the surrounding and reduce environmental pollution and the generation of clean energy Lakes.

13. Achieving sustainable neighborhoods Riyadh: The majority of reviving Riyadh with networking style city, and that the ownership of the land plays a big role in the applicability of environmental sustainability issues in neighborhoods as a result of the multiplicity of land holdings and based on neighborhood management to more than administrative and regulatory body, and therefore the applicability of the principle of environmental sustainability is achieved in the control and the positive results in neighborhoods own and which fall under a separate department or private ownership and therefore were selected housing faculty members live at King Saud University for the application of case study, and to represent this type of neighborhoods to one of Riyadh patterns, and numerous properties owned by the neighborhood and which are: - The occurrence of the neighborhood within the ownership and management of one. - Chronological age of the neighborhood asymptotic to all districts of the city of Riyadh is a case study of a balanced away from the traditional and old dilapidated neighborhoods, as well as new and updated neighborhoods. - The possibility of achieving environmental sustainability in the neighborhood by the competent authorities, and as a successful example applied to achieve the sustainability of residential neighborhoods in Riyadh. The table below shows the results of four-wheel analysis of environmental issues in the neighborhood housing the King Saud University in Riyadh. TABLE II shows analysis result of land use , green spaces and urban form. Weakness

Multiple patterns of housing units to meet the needs of families in the size of the units used, the balance in the internal spaces and the total area of residential units, space, proportion and balance of open spaces. - Is designed residential towers pattern achieves good ventilation and solarization housing units and high-rebound entitled to benefit from the positive solar design and natural resources and take advantage of solar radiation and wind movement. - Availability of good urban spaces between the spaces of residential towers and the dimensions of the ideal lengths between them and residential towers, is a private recreational spaces to residential towers.

Failure to provide an elementary school district under the pretext of the neighborhood near the school compound is (550 m) but the educational complex is located outside the wall of the neighborhood, which requires students connect using the vehicles. - Cover the green spaces (6%) only from the area of the project, has been allocated one park only for the neighborhood area (0.4 hectares), a positive impact is to increase green spaces in the neighborhood to reduce carbon emission rate, and create the perfect environmentally and aesthetically pleasing plant environment. - The residential blocks of villas closed and only in a manner designed to open the local streets of the neighborhood, has not been allocated places a green residential blocks to enhance social networking and recreational area for children. Threats

Optimal planning of land use , green spaces and urban form:

Strength

Opportunities - Develop an effective attraction points in the footpaths used to activate even more, and work on the plantation in check mislead the crossing to reduce the use of vehicles in the neighborhood. - Mislead the trees for urban spaces within the district is working on a micro climate change (Microclimate) and reduce the heat island effect in summer and winter working to block the movement of wind non-grainy. - Increasing the landscaping and plants to increase the rate of biomass that can be used in power generation.

- The lack of spaces for the development of urban green spaces or for future expansion or for the development of basic services to the neighborhood elementary teacher.

Energy:

TABLE III shows analysis result of Energy use. Strength - Activate the use of solar panels on the roofs of buildings, parking lots and the use of new electric grid of the neighborhood network independent of the city. - Environmental characteristics surrounding the exploitation of solar energy and take advantage of solar radiation. Opportunities - Take advantage of the natural energies surrounding solar energy geothermal energy and wind energy. - The interaction of the competent authorities towards the use of renewable energy systems in buildings. - Rapid growth in energy demand increase. - The proliferation of devices and units with high-efficiency lighting energy consumption.

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Weakness - The cost of production of electric power to residential buildings and a very low rate of up to kW (5 Hallals) which is equivalent to (1.4 US cents). Threats - Lack of demand for sustainable energy. - The high cost of implementation and maintenance. - Increasing the rate of carbon emissions due to burning fossil fuels for energy production

TABLE IV shows analysis result of Water and sanitation use.

Water and sanitation:

Strength - Good drainage of rain water in the neighborhood puts practical vision to take advantage of them and good drainage of the neighborhood reduces the availability of places of injected water.

Opportunities - Develop strategies for rationalization of water consumption in the neighborhood through new technologies that reduce the rate of consumption in toilets, washing and kitchen faucet water. - Take advantage of the amount of rainwater in the neighborhood through fetching water techniques (Blue Roof) or green surfaces, or through the existing terrestrial channels in the neighborhood and filtering water and use them for irrigation and washing. - Take advantage of the gray water from the sewage of up to (4800 cubic meters / day) and used for irrigation and washing vehicles, sidewalks and feed the fountains working to soften the atmosphere is warm and dry in summer. - Take advantage of fertilizers and slag in the sewage plant before being processed and used to generate the membership used for cooking or heating in winter or running hybrid vehicles energy.

Weakness - A very high percentage of the average per capita consumption of water in the neighborhood where was (1.34 cubic meters / day) compared to an average per capita consumption in the city, who arrived in (0.372 cubic meters / day). - Not to take advantage of the gray water from sewage or rainwater. Threats - Lack of fresh water sources of the neighborhood and the city in general. - Increase the actual water consumption rate of residents of the neighborhood for per capita consumption in the city, reaching almost three-fold, and increase consumption growth rate by increasing the time period. - The high cost of desalination of sea water to produce water where the cost per cubic meter of desalinated water one US dollar a comprehensive transportation from the nearest stations located in the east coast of the Queen to the city (the General Establishment for Water Desalination.2015). - The neighborhood and the city is located within the geographical scope of who is suffering from scarcity of rain water, and the lack of this water resource less expensive than other methods.

14. Recommendations: There are several sustainable solutions and techniques used to achieve sustainability in residential neighborhoods, by taking advantage of the surrounding resources of solar energy and energy-floor heating and wind power and energy of the seas and oceans, and take advantage of the waste and turn it into used for heating, cooking and running mobility vehicles inside the neighborhood clean energy. The possibility of achieving a sustainable residential neighborhoods by taking advantage of globally successful examples and techniques required to achieve self-energy residential neighborhoods sufficiency. To achieve the sustainable residential neighborhoods in Riyadh city requires taking into account the environmental and climate change and raise awareness of the importance of conservation of the environment among the community, and it can take advantage of opportunities and promotion to increase the strengths of the neighborhood, address weaknesses and taking into account the threats to pursue the sustainability of neighborhoods in the city of Riyadh

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Software Configuration Management using the Dependency Information Junku Lee1, Dongyeon Kim2, and Sangjun Lee3 1

Department of Software Convergence, Soongsil University, 369, Sangdo-ro, Dongjak-gu, Seoul, Korea (e-mail: [email protected]) 2 Department of Software Convergence, Soongsil University, 369, Sangdo-ro, Dongjak-gu, Seoul, Korea (e-mail: [email protected]) 3 Department of Software Convergence, Soongsil University, 369, Sangdo-ro, Dongjak-gu, Seoul, Korea (corresponding author’s phone: +82-2-820-0672, e-mail: [email protected])

Abstract: As the Software industry develops and a project becomes bigger, the importance of configuration management is increasing. The existing software configuration management system has the limit in analyzing the functional dependence of the modified parts. In this paper, we propose the software configuration management for grasping the functional dependences of the modified code. In addition, we present the webhard synchronization function about project in order to improve the software development productivity. The proposed software configuration management system provides easiness about the server re-establishment by grasping the functional dependence through the flag of the inside of the source code.

Keywords: Software Configuration, Dependency Information, Project Management, Web Hard

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